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authorjdgleaver2021-09-17 10:37:49 +0100
committerjdgleaver2021-09-17 10:37:49 +0100
commit7d871ab87d45e535d1512a5834b627cbbce2e66c (patch)
tree8b6932a6eb0f786ea8e922701a0182396a80a7cc /libretro-common/include/libretro.h
parentf53deef14f98c659fe9bbd7684656ee88977acbd (diff)
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Replace direct direct file access with VFS routines
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diff --git a/libretro-common/include/libretro.h b/libretro-common/include/libretro.h
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+/* Copyright (C) 2010-2020 The RetroArch team
+ *
+ * ---------------------------------------------------------------------------------------
+ * The following license statement only applies to this libretro API header (libretro.h).
+ * ---------------------------------------------------------------------------------------
+ *
+ * Permission is hereby granted, free of charge,
+ * to any person obtaining a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef LIBRETRO_H__
+#define LIBRETRO_H__
+
+#include <stdint.h>
+#include <stddef.h>
+#include <limits.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef __cplusplus
+#if defined(_MSC_VER) && _MSC_VER < 1800 && !defined(SN_TARGET_PS3)
+/* Hack applied for MSVC when compiling in C89 mode
+ * as it isn't C99-compliant. */
+#define bool unsigned char
+#define true 1
+#define false 0
+#else
+#include <stdbool.h>
+#endif
+#endif
+
+#ifndef RETRO_CALLCONV
+# if defined(__GNUC__) && defined(__i386__) && !defined(__x86_64__)
+# define RETRO_CALLCONV __attribute__((cdecl))
+# elif defined(_MSC_VER) && defined(_M_X86) && !defined(_M_X64)
+# define RETRO_CALLCONV __cdecl
+# else
+# define RETRO_CALLCONV /* all other platforms only have one calling convention each */
+# endif
+#endif
+
+#ifndef RETRO_API
+# if defined(_WIN32) || defined(__CYGWIN__) || defined(__MINGW32__)
+# ifdef RETRO_IMPORT_SYMBOLS
+# ifdef __GNUC__
+# define RETRO_API RETRO_CALLCONV __attribute__((__dllimport__))
+# else
+# define RETRO_API RETRO_CALLCONV __declspec(dllimport)
+# endif
+# else
+# ifdef __GNUC__
+# define RETRO_API RETRO_CALLCONV __attribute__((__dllexport__))
+# else
+# define RETRO_API RETRO_CALLCONV __declspec(dllexport)
+# endif
+# endif
+# else
+# if defined(__GNUC__) && __GNUC__ >= 4
+# define RETRO_API RETRO_CALLCONV __attribute__((__visibility__("default")))
+# else
+# define RETRO_API RETRO_CALLCONV
+# endif
+# endif
+#endif
+
+/* Used for checking API/ABI mismatches that can break libretro
+ * implementations.
+ * It is not incremented for compatible changes to the API.
+ */
+#define RETRO_API_VERSION 1
+
+/*
+ * Libretro's fundamental device abstractions.
+ *
+ * Libretro's input system consists of some standardized device types,
+ * such as a joypad (with/without analog), mouse, keyboard, lightgun
+ * and a pointer.
+ *
+ * The functionality of these devices are fixed, and individual cores
+ * map their own concept of a controller to libretro's abstractions.
+ * This makes it possible for frontends to map the abstract types to a
+ * real input device, and not having to worry about binding input
+ * correctly to arbitrary controller layouts.
+ */
+
+#define RETRO_DEVICE_TYPE_SHIFT 8
+#define RETRO_DEVICE_MASK ((1 << RETRO_DEVICE_TYPE_SHIFT) - 1)
+#define RETRO_DEVICE_SUBCLASS(base, id) (((id + 1) << RETRO_DEVICE_TYPE_SHIFT) | base)
+
+/* Input disabled. */
+#define RETRO_DEVICE_NONE 0
+
+/* The JOYPAD is called RetroPad. It is essentially a Super Nintendo
+ * controller, but with additional L2/R2/L3/R3 buttons, similar to a
+ * PS1 DualShock. */
+#define RETRO_DEVICE_JOYPAD 1
+
+/* The mouse is a simple mouse, similar to Super Nintendo's mouse.
+ * X and Y coordinates are reported relatively to last poll (poll callback).
+ * It is up to the libretro implementation to keep track of where the mouse
+ * pointer is supposed to be on the screen.
+ * The frontend must make sure not to interfere with its own hardware
+ * mouse pointer.
+ */
+#define RETRO_DEVICE_MOUSE 2
+
+/* KEYBOARD device lets one poll for raw key pressed.
+ * It is poll based, so input callback will return with the current
+ * pressed state.
+ * For event/text based keyboard input, see
+ * RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK.
+ */
+#define RETRO_DEVICE_KEYBOARD 3
+
+/* LIGHTGUN device is similar to Guncon-2 for PlayStation 2.
+ * It reports X/Y coordinates in screen space (similar to the pointer)
+ * in the range [-0x8000, 0x7fff] in both axes, with zero being center and
+ * -0x8000 being out of bounds.
+ * As well as reporting on/off screen state. It features a trigger,
+ * start/select buttons, auxiliary action buttons and a
+ * directional pad. A forced off-screen shot can be requested for
+ * auto-reloading function in some games.
+ */
+#define RETRO_DEVICE_LIGHTGUN 4
+
+/* The ANALOG device is an extension to JOYPAD (RetroPad).
+ * Similar to DualShock2 it adds two analog sticks and all buttons can
+ * be analog. This is treated as a separate device type as it returns
+ * axis values in the full analog range of [-0x7fff, 0x7fff],
+ * although some devices may return -0x8000.
+ * Positive X axis is right. Positive Y axis is down.
+ * Buttons are returned in the range [0, 0x7fff].
+ * Only use ANALOG type when polling for analog values.
+ */
+#define RETRO_DEVICE_ANALOG 5
+
+/* Abstracts the concept of a pointing mechanism, e.g. touch.
+ * This allows libretro to query in absolute coordinates where on the
+ * screen a mouse (or something similar) is being placed.
+ * For a touch centric device, coordinates reported are the coordinates
+ * of the press.
+ *
+ * Coordinates in X and Y are reported as:
+ * [-0x7fff, 0x7fff]: -0x7fff corresponds to the far left/top of the screen,
+ * and 0x7fff corresponds to the far right/bottom of the screen.
+ * The "screen" is here defined as area that is passed to the frontend and
+ * later displayed on the monitor.
+ *
+ * The frontend is free to scale/resize this screen as it sees fit, however,
+ * (X, Y) = (-0x7fff, -0x7fff) will correspond to the top-left pixel of the
+ * game image, etc.
+ *
+ * To check if the pointer coordinates are valid (e.g. a touch display
+ * actually being touched), PRESSED returns 1 or 0.
+ *
+ * If using a mouse on a desktop, PRESSED will usually correspond to the
+ * left mouse button, but this is a frontend decision.
+ * PRESSED will only return 1 if the pointer is inside the game screen.
+ *
+ * For multi-touch, the index variable can be used to successively query
+ * more presses.
+ * If index = 0 returns true for _PRESSED, coordinates can be extracted
+ * with _X, _Y for index = 0. One can then query _PRESSED, _X, _Y with
+ * index = 1, and so on.
+ * Eventually _PRESSED will return false for an index. No further presses
+ * are registered at this point. */
+#define RETRO_DEVICE_POINTER 6
+
+/* Buttons for the RetroPad (JOYPAD).
+ * The placement of these is equivalent to placements on the
+ * Super Nintendo controller.
+ * L2/R2/L3/R3 buttons correspond to the PS1 DualShock.
+ * Also used as id values for RETRO_DEVICE_INDEX_ANALOG_BUTTON */
+#define RETRO_DEVICE_ID_JOYPAD_B 0
+#define RETRO_DEVICE_ID_JOYPAD_Y 1
+#define RETRO_DEVICE_ID_JOYPAD_SELECT 2
+#define RETRO_DEVICE_ID_JOYPAD_START 3
+#define RETRO_DEVICE_ID_JOYPAD_UP 4
+#define RETRO_DEVICE_ID_JOYPAD_DOWN 5
+#define RETRO_DEVICE_ID_JOYPAD_LEFT 6
+#define RETRO_DEVICE_ID_JOYPAD_RIGHT 7
+#define RETRO_DEVICE_ID_JOYPAD_A 8
+#define RETRO_DEVICE_ID_JOYPAD_X 9
+#define RETRO_DEVICE_ID_JOYPAD_L 10
+#define RETRO_DEVICE_ID_JOYPAD_R 11
+#define RETRO_DEVICE_ID_JOYPAD_L2 12
+#define RETRO_DEVICE_ID_JOYPAD_R2 13
+#define RETRO_DEVICE_ID_JOYPAD_L3 14
+#define RETRO_DEVICE_ID_JOYPAD_R3 15
+
+#define RETRO_DEVICE_ID_JOYPAD_MASK 256
+
+/* Index / Id values for ANALOG device. */
+#define RETRO_DEVICE_INDEX_ANALOG_LEFT 0
+#define RETRO_DEVICE_INDEX_ANALOG_RIGHT 1
+#define RETRO_DEVICE_INDEX_ANALOG_BUTTON 2
+#define RETRO_DEVICE_ID_ANALOG_X 0
+#define RETRO_DEVICE_ID_ANALOG_Y 1
+
+/* Id values for MOUSE. */
+#define RETRO_DEVICE_ID_MOUSE_X 0
+#define RETRO_DEVICE_ID_MOUSE_Y 1
+#define RETRO_DEVICE_ID_MOUSE_LEFT 2
+#define RETRO_DEVICE_ID_MOUSE_RIGHT 3
+#define RETRO_DEVICE_ID_MOUSE_WHEELUP 4
+#define RETRO_DEVICE_ID_MOUSE_WHEELDOWN 5
+#define RETRO_DEVICE_ID_MOUSE_MIDDLE 6
+#define RETRO_DEVICE_ID_MOUSE_HORIZ_WHEELUP 7
+#define RETRO_DEVICE_ID_MOUSE_HORIZ_WHEELDOWN 8
+#define RETRO_DEVICE_ID_MOUSE_BUTTON_4 9
+#define RETRO_DEVICE_ID_MOUSE_BUTTON_5 10
+
+/* Id values for LIGHTGUN. */
+#define RETRO_DEVICE_ID_LIGHTGUN_SCREEN_X 13 /*Absolute Position*/
+#define RETRO_DEVICE_ID_LIGHTGUN_SCREEN_Y 14 /*Absolute*/
+#define RETRO_DEVICE_ID_LIGHTGUN_IS_OFFSCREEN 15 /*Status Check*/
+#define RETRO_DEVICE_ID_LIGHTGUN_TRIGGER 2
+#define RETRO_DEVICE_ID_LIGHTGUN_RELOAD 16 /*Forced off-screen shot*/
+#define RETRO_DEVICE_ID_LIGHTGUN_AUX_A 3
+#define RETRO_DEVICE_ID_LIGHTGUN_AUX_B 4
+#define RETRO_DEVICE_ID_LIGHTGUN_START 6
+#define RETRO_DEVICE_ID_LIGHTGUN_SELECT 7
+#define RETRO_DEVICE_ID_LIGHTGUN_AUX_C 8
+#define RETRO_DEVICE_ID_LIGHTGUN_DPAD_UP 9
+#define RETRO_DEVICE_ID_LIGHTGUN_DPAD_DOWN 10
+#define RETRO_DEVICE_ID_LIGHTGUN_DPAD_LEFT 11
+#define RETRO_DEVICE_ID_LIGHTGUN_DPAD_RIGHT 12
+/* deprecated */
+#define RETRO_DEVICE_ID_LIGHTGUN_X 0 /*Relative Position*/
+#define RETRO_DEVICE_ID_LIGHTGUN_Y 1 /*Relative*/
+#define RETRO_DEVICE_ID_LIGHTGUN_CURSOR 3 /*Use Aux:A*/
+#define RETRO_DEVICE_ID_LIGHTGUN_TURBO 4 /*Use Aux:B*/
+#define RETRO_DEVICE_ID_LIGHTGUN_PAUSE 5 /*Use Start*/
+
+/* Id values for POINTER. */
+#define RETRO_DEVICE_ID_POINTER_X 0
+#define RETRO_DEVICE_ID_POINTER_Y 1
+#define RETRO_DEVICE_ID_POINTER_PRESSED 2
+#define RETRO_DEVICE_ID_POINTER_COUNT 3
+
+/* Returned from retro_get_region(). */
+#define RETRO_REGION_NTSC 0
+#define RETRO_REGION_PAL 1
+
+/* Id values for LANGUAGE */
+enum retro_language
+{
+ RETRO_LANGUAGE_ENGLISH = 0,
+ RETRO_LANGUAGE_JAPANESE = 1,
+ RETRO_LANGUAGE_FRENCH = 2,
+ RETRO_LANGUAGE_SPANISH = 3,
+ RETRO_LANGUAGE_GERMAN = 4,
+ RETRO_LANGUAGE_ITALIAN = 5,
+ RETRO_LANGUAGE_DUTCH = 6,
+ RETRO_LANGUAGE_PORTUGUESE_BRAZIL = 7,
+ RETRO_LANGUAGE_PORTUGUESE_PORTUGAL = 8,
+ RETRO_LANGUAGE_RUSSIAN = 9,
+ RETRO_LANGUAGE_KOREAN = 10,
+ RETRO_LANGUAGE_CHINESE_TRADITIONAL = 11,
+ RETRO_LANGUAGE_CHINESE_SIMPLIFIED = 12,
+ RETRO_LANGUAGE_ESPERANTO = 13,
+ RETRO_LANGUAGE_POLISH = 14,
+ RETRO_LANGUAGE_VIETNAMESE = 15,
+ RETRO_LANGUAGE_ARABIC = 16,
+ RETRO_LANGUAGE_GREEK = 17,
+ RETRO_LANGUAGE_TURKISH = 18,
+ RETRO_LANGUAGE_SLOVAK = 19,
+ RETRO_LANGUAGE_PERSIAN = 20,
+ RETRO_LANGUAGE_HEBREW = 21,
+ RETRO_LANGUAGE_ASTURIAN = 22,
+ RETRO_LANGUAGE_FINNISH = 23,
+ RETRO_LANGUAGE_LAST,
+
+ /* Ensure sizeof(enum) == sizeof(int) */
+ RETRO_LANGUAGE_DUMMY = INT_MAX
+};
+
+/* Passed to retro_get_memory_data/size().
+ * If the memory type doesn't apply to the
+ * implementation NULL/0 can be returned.
+ */
+#define RETRO_MEMORY_MASK 0xff
+
+/* Regular save RAM. This RAM is usually found on a game cartridge,
+ * backed up by a battery.
+ * If save game data is too complex for a single memory buffer,
+ * the SAVE_DIRECTORY (preferably) or SYSTEM_DIRECTORY environment
+ * callback can be used. */
+#define RETRO_MEMORY_SAVE_RAM 0
+
+/* Some games have a built-in clock to keep track of time.
+ * This memory is usually just a couple of bytes to keep track of time.
+ */
+#define RETRO_MEMORY_RTC 1
+
+/* System ram lets a frontend peek into a game systems main RAM. */
+#define RETRO_MEMORY_SYSTEM_RAM 2
+
+/* Video ram lets a frontend peek into a game systems video RAM (VRAM). */
+#define RETRO_MEMORY_VIDEO_RAM 3
+
+/* Keysyms used for ID in input state callback when polling RETRO_KEYBOARD. */
+enum retro_key
+{
+ RETROK_UNKNOWN = 0,
+ RETROK_FIRST = 0,
+ RETROK_BACKSPACE = 8,
+ RETROK_TAB = 9,
+ RETROK_CLEAR = 12,
+ RETROK_RETURN = 13,
+ RETROK_PAUSE = 19,
+ RETROK_ESCAPE = 27,
+ RETROK_SPACE = 32,
+ RETROK_EXCLAIM = 33,
+ RETROK_QUOTEDBL = 34,
+ RETROK_HASH = 35,
+ RETROK_DOLLAR = 36,
+ RETROK_AMPERSAND = 38,
+ RETROK_QUOTE = 39,
+ RETROK_LEFTPAREN = 40,
+ RETROK_RIGHTPAREN = 41,
+ RETROK_ASTERISK = 42,
+ RETROK_PLUS = 43,
+ RETROK_COMMA = 44,
+ RETROK_MINUS = 45,
+ RETROK_PERIOD = 46,
+ RETROK_SLASH = 47,
+ RETROK_0 = 48,
+ RETROK_1 = 49,
+ RETROK_2 = 50,
+ RETROK_3 = 51,
+ RETROK_4 = 52,
+ RETROK_5 = 53,
+ RETROK_6 = 54,
+ RETROK_7 = 55,
+ RETROK_8 = 56,
+ RETROK_9 = 57,
+ RETROK_COLON = 58,
+ RETROK_SEMICOLON = 59,
+ RETROK_LESS = 60,
+ RETROK_EQUALS = 61,
+ RETROK_GREATER = 62,
+ RETROK_QUESTION = 63,
+ RETROK_AT = 64,
+ RETROK_LEFTBRACKET = 91,
+ RETROK_BACKSLASH = 92,
+ RETROK_RIGHTBRACKET = 93,
+ RETROK_CARET = 94,
+ RETROK_UNDERSCORE = 95,
+ RETROK_BACKQUOTE = 96,
+ RETROK_a = 97,
+ RETROK_b = 98,
+ RETROK_c = 99,
+ RETROK_d = 100,
+ RETROK_e = 101,
+ RETROK_f = 102,
+ RETROK_g = 103,
+ RETROK_h = 104,
+ RETROK_i = 105,
+ RETROK_j = 106,
+ RETROK_k = 107,
+ RETROK_l = 108,
+ RETROK_m = 109,
+ RETROK_n = 110,
+ RETROK_o = 111,
+ RETROK_p = 112,
+ RETROK_q = 113,
+ RETROK_r = 114,
+ RETROK_s = 115,
+ RETROK_t = 116,
+ RETROK_u = 117,
+ RETROK_v = 118,
+ RETROK_w = 119,
+ RETROK_x = 120,
+ RETROK_y = 121,
+ RETROK_z = 122,
+ RETROK_LEFTBRACE = 123,
+ RETROK_BAR = 124,
+ RETROK_RIGHTBRACE = 125,
+ RETROK_TILDE = 126,
+ RETROK_DELETE = 127,
+
+ RETROK_KP0 = 256,
+ RETROK_KP1 = 257,
+ RETROK_KP2 = 258,
+ RETROK_KP3 = 259,
+ RETROK_KP4 = 260,
+ RETROK_KP5 = 261,
+ RETROK_KP6 = 262,
+ RETROK_KP7 = 263,
+ RETROK_KP8 = 264,
+ RETROK_KP9 = 265,
+ RETROK_KP_PERIOD = 266,
+ RETROK_KP_DIVIDE = 267,
+ RETROK_KP_MULTIPLY = 268,
+ RETROK_KP_MINUS = 269,
+ RETROK_KP_PLUS = 270,
+ RETROK_KP_ENTER = 271,
+ RETROK_KP_EQUALS = 272,
+
+ RETROK_UP = 273,
+ RETROK_DOWN = 274,
+ RETROK_RIGHT = 275,
+ RETROK_LEFT = 276,
+ RETROK_INSERT = 277,
+ RETROK_HOME = 278,
+ RETROK_END = 279,
+ RETROK_PAGEUP = 280,
+ RETROK_PAGEDOWN = 281,
+
+ RETROK_F1 = 282,
+ RETROK_F2 = 283,
+ RETROK_F3 = 284,
+ RETROK_F4 = 285,
+ RETROK_F5 = 286,
+ RETROK_F6 = 287,
+ RETROK_F7 = 288,
+ RETROK_F8 = 289,
+ RETROK_F9 = 290,
+ RETROK_F10 = 291,
+ RETROK_F11 = 292,
+ RETROK_F12 = 293,
+ RETROK_F13 = 294,
+ RETROK_F14 = 295,
+ RETROK_F15 = 296,
+
+ RETROK_NUMLOCK = 300,
+ RETROK_CAPSLOCK = 301,
+ RETROK_SCROLLOCK = 302,
+ RETROK_RSHIFT = 303,
+ RETROK_LSHIFT = 304,
+ RETROK_RCTRL = 305,
+ RETROK_LCTRL = 306,
+ RETROK_RALT = 307,
+ RETROK_LALT = 308,
+ RETROK_RMETA = 309,
+ RETROK_LMETA = 310,
+ RETROK_LSUPER = 311,
+ RETROK_RSUPER = 312,
+ RETROK_MODE = 313,
+ RETROK_COMPOSE = 314,
+
+ RETROK_HELP = 315,
+ RETROK_PRINT = 316,
+ RETROK_SYSREQ = 317,
+ RETROK_BREAK = 318,
+ RETROK_MENU = 319,
+ RETROK_POWER = 320,
+ RETROK_EURO = 321,
+ RETROK_UNDO = 322,
+ RETROK_OEM_102 = 323,
+
+ RETROK_LAST,
+
+ RETROK_DUMMY = INT_MAX /* Ensure sizeof(enum) == sizeof(int) */
+};
+
+enum retro_mod
+{
+ RETROKMOD_NONE = 0x0000,
+
+ RETROKMOD_SHIFT = 0x01,
+ RETROKMOD_CTRL = 0x02,
+ RETROKMOD_ALT = 0x04,
+ RETROKMOD_META = 0x08,
+
+ RETROKMOD_NUMLOCK = 0x10,
+ RETROKMOD_CAPSLOCK = 0x20,
+ RETROKMOD_SCROLLOCK = 0x40,
+
+ RETROKMOD_DUMMY = INT_MAX /* Ensure sizeof(enum) == sizeof(int) */
+};
+
+/* If set, this call is not part of the public libretro API yet. It can
+ * change or be removed at any time. */
+#define RETRO_ENVIRONMENT_EXPERIMENTAL 0x10000
+/* Environment callback to be used internally in frontend. */
+#define RETRO_ENVIRONMENT_PRIVATE 0x20000
+
+/* Environment commands. */
+#define RETRO_ENVIRONMENT_SET_ROTATION 1 /* const unsigned * --
+ * Sets screen rotation of graphics.
+ * Valid values are 0, 1, 2, 3, which rotates screen by 0, 90, 180,
+ * 270 degrees counter-clockwise respectively.
+ */
+#define RETRO_ENVIRONMENT_GET_OVERSCAN 2 /* bool * --
+ * NOTE: As of 2019 this callback is considered deprecated in favor of
+ * using core options to manage overscan in a more nuanced, core-specific way.
+ *
+ * Boolean value whether or not the implementation should use overscan,
+ * or crop away overscan.
+ */
+#define RETRO_ENVIRONMENT_GET_CAN_DUPE 3 /* bool * --
+ * Boolean value whether or not frontend supports frame duping,
+ * passing NULL to video frame callback.
+ */
+
+ /* Environ 4, 5 are no longer supported (GET_VARIABLE / SET_VARIABLES),
+ * and reserved to avoid possible ABI clash.
+ */
+
+#define RETRO_ENVIRONMENT_SET_MESSAGE 6 /* const struct retro_message * --
+ * Sets a message to be displayed in implementation-specific manner
+ * for a certain amount of 'frames'.
+ * Should not be used for trivial messages, which should simply be
+ * logged via RETRO_ENVIRONMENT_GET_LOG_INTERFACE (or as a
+ * fallback, stderr).
+ */
+#define RETRO_ENVIRONMENT_SHUTDOWN 7 /* N/A (NULL) --
+ * Requests the frontend to shutdown.
+ * Should only be used if game has a specific
+ * way to shutdown the game from a menu item or similar.
+ */
+#define RETRO_ENVIRONMENT_SET_PERFORMANCE_LEVEL 8
+ /* const unsigned * --
+ * Gives a hint to the frontend how demanding this implementation
+ * is on a system. E.g. reporting a level of 2 means
+ * this implementation should run decently on all frontends
+ * of level 2 and up.
+ *
+ * It can be used by the frontend to potentially warn
+ * about too demanding implementations.
+ *
+ * The levels are "floating".
+ *
+ * This function can be called on a per-game basis,
+ * as certain games an implementation can play might be
+ * particularly demanding.
+ * If called, it should be called in retro_load_game().
+ */
+#define RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY 9
+ /* const char ** --
+ * Returns the "system" directory of the frontend.
+ * This directory can be used to store system specific
+ * content such as BIOSes, configuration data, etc.
+ * The returned value can be NULL.
+ * If so, no such directory is defined,
+ * and it's up to the implementation to find a suitable directory.
+ *
+ * NOTE: Some cores used this folder also for "save" data such as
+ * memory cards, etc, for lack of a better place to put it.
+ * This is now discouraged, and if possible, cores should try to
+ * use the new GET_SAVE_DIRECTORY.
+ */
+#define RETRO_ENVIRONMENT_SET_PIXEL_FORMAT 10
+ /* const enum retro_pixel_format * --
+ * Sets the internal pixel format used by the implementation.
+ * The default pixel format is RETRO_PIXEL_FORMAT_0RGB1555.
+ * This pixel format however, is deprecated (see enum retro_pixel_format).
+ * If the call returns false, the frontend does not support this pixel
+ * format.
+ *
+ * This function should be called inside retro_load_game() or
+ * retro_get_system_av_info().
+ */
+#define RETRO_ENVIRONMENT_SET_INPUT_DESCRIPTORS 11
+ /* const struct retro_input_descriptor * --
+ * Sets an array of retro_input_descriptors.
+ * It is up to the frontend to present this in a usable way.
+ * The array is terminated by retro_input_descriptor::description
+ * being set to NULL.
+ * This function can be called at any time, but it is recommended
+ * to call it as early as possible.
+ */
+#define RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK 12
+ /* const struct retro_keyboard_callback * --
+ * Sets a callback function used to notify core about keyboard events.
+ */
+#define RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE 13
+ /* const struct retro_disk_control_callback * --
+ * Sets an interface which frontend can use to eject and insert
+ * disk images.
+ * This is used for games which consist of multiple images and
+ * must be manually swapped out by the user (e.g. PSX).
+ */
+#define RETRO_ENVIRONMENT_SET_HW_RENDER 14
+ /* struct retro_hw_render_callback * --
+ * Sets an interface to let a libretro core render with
+ * hardware acceleration.
+ * Should be called in retro_load_game().
+ * If successful, libretro cores will be able to render to a
+ * frontend-provided framebuffer.
+ * The size of this framebuffer will be at least as large as
+ * max_width/max_height provided in get_av_info().
+ * If HW rendering is used, pass only RETRO_HW_FRAME_BUFFER_VALID or
+ * NULL to retro_video_refresh_t.
+ */
+#define RETRO_ENVIRONMENT_GET_VARIABLE 15
+ /* struct retro_variable * --
+ * Interface to acquire user-defined information from environment
+ * that cannot feasibly be supported in a multi-system way.
+ * 'key' should be set to a key which has already been set by
+ * SET_VARIABLES.
+ * 'data' will be set to a value or NULL.
+ */
+#define RETRO_ENVIRONMENT_SET_VARIABLES 16
+ /* const struct retro_variable * --
+ * Allows an implementation to signal the environment
+ * which variables it might want to check for later using
+ * GET_VARIABLE.
+ * This allows the frontend to present these variables to
+ * a user dynamically.
+ * This should be called the first time as early as
+ * possible (ideally in retro_set_environment).
+ * Afterward it may be called again for the core to communicate
+ * updated options to the frontend, but the number of core
+ * options must not change from the number in the initial call.
+ *
+ * 'data' points to an array of retro_variable structs
+ * terminated by a { NULL, NULL } element.
+ * retro_variable::key should be namespaced to not collide
+ * with other implementations' keys. E.g. A core called
+ * 'foo' should use keys named as 'foo_option'.
+ * retro_variable::value should contain a human readable
+ * description of the key as well as a '|' delimited list
+ * of expected values.
+ *
+ * The number of possible options should be very limited,
+ * i.e. it should be feasible to cycle through options
+ * without a keyboard.
+ *
+ * First entry should be treated as a default.
+ *
+ * Example entry:
+ * { "foo_option", "Speed hack coprocessor X; false|true" }
+ *
+ * Text before first ';' is description. This ';' must be
+ * followed by a space, and followed by a list of possible
+ * values split up with '|'.
+ *
+ * Only strings are operated on. The possible values will
+ * generally be displayed and stored as-is by the frontend.
+ */
+#define RETRO_ENVIRONMENT_GET_VARIABLE_UPDATE 17
+ /* bool * --
+ * Result is set to true if some variables are updated by
+ * frontend since last call to RETRO_ENVIRONMENT_GET_VARIABLE.
+ * Variables should be queried with GET_VARIABLE.
+ */
+#define RETRO_ENVIRONMENT_SET_SUPPORT_NO_GAME 18
+ /* const bool * --
+ * If true, the libretro implementation supports calls to
+ * retro_load_game() with NULL as argument.
+ * Used by cores which can run without particular game data.
+ * This should be called within retro_set_environment() only.
+ */
+#define RETRO_ENVIRONMENT_GET_LIBRETRO_PATH 19
+ /* const char ** --
+ * Retrieves the absolute path from where this libretro
+ * implementation was loaded.
+ * NULL is returned if the libretro was loaded statically
+ * (i.e. linked statically to frontend), or if the path cannot be
+ * determined.
+ * Mostly useful in cooperation with SET_SUPPORT_NO_GAME as assets can
+ * be loaded without ugly hacks.
+ */
+
+ /* Environment 20 was an obsolete version of SET_AUDIO_CALLBACK.
+ * It was not used by any known core at the time,
+ * and was removed from the API. */
+#define RETRO_ENVIRONMENT_SET_FRAME_TIME_CALLBACK 21
+ /* const struct retro_frame_time_callback * --
+ * Lets the core know how much time has passed since last
+ * invocation of retro_run().
+ * The frontend can tamper with the timing to fake fast-forward,
+ * slow-motion, frame stepping, etc.
+ * In this case the delta time will use the reference value
+ * in frame_time_callback..
+ */
+#define RETRO_ENVIRONMENT_SET_AUDIO_CALLBACK 22
+ /* const struct retro_audio_callback * --
+ * Sets an interface which is used to notify a libretro core about audio
+ * being available for writing.
+ * The callback can be called from any thread, so a core using this must
+ * have a thread safe audio implementation.
+ * It is intended for games where audio and video are completely
+ * asynchronous and audio can be generated on the fly.
+ * This interface is not recommended for use with emulators which have
+ * highly synchronous audio.
+ *
+ * The callback only notifies about writability; the libretro core still
+ * has to call the normal audio callbacks
+ * to write audio. The audio callbacks must be called from within the
+ * notification callback.
+ * The amount of audio data to write is up to the implementation.
+ * Generally, the audio callback will be called continously in a loop.
+ *
+ * Due to thread safety guarantees and lack of sync between audio and
+ * video, a frontend can selectively disallow this interface based on
+ * internal configuration. A core using this interface must also
+ * implement the "normal" audio interface.
+ *
+ * A libretro core using SET_AUDIO_CALLBACK should also make use of
+ * SET_FRAME_TIME_CALLBACK.
+ */
+#define RETRO_ENVIRONMENT_GET_RUMBLE_INTERFACE 23
+ /* struct retro_rumble_interface * --
+ * Gets an interface which is used by a libretro core to set
+ * state of rumble motors in controllers.
+ * A strong and weak motor is supported, and they can be
+ * controlled indepedently.
+ * Should be called from either retro_init() or retro_load_game().
+ * Should not be called from retro_set_environment().
+ * Returns false if rumble functionality is unavailable.
+ */
+#define RETRO_ENVIRONMENT_GET_INPUT_DEVICE_CAPABILITIES 24
+ /* uint64_t * --
+ * Gets a bitmask telling which device type are expected to be
+ * handled properly in a call to retro_input_state_t.
+ * Devices which are not handled or recognized always return
+ * 0 in retro_input_state_t.
+ * Example bitmask: caps = (1 << RETRO_DEVICE_JOYPAD) | (1 << RETRO_DEVICE_ANALOG).
+ * Should only be called in retro_run().
+ */
+#define RETRO_ENVIRONMENT_GET_SENSOR_INTERFACE (25 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* struct retro_sensor_interface * --
+ * Gets access to the sensor interface.
+ * The purpose of this interface is to allow
+ * setting state related to sensors such as polling rate,
+ * enabling/disable it entirely, etc.
+ * Reading sensor state is done via the normal
+ * input_state_callback API.
+ */
+#define RETRO_ENVIRONMENT_GET_CAMERA_INTERFACE (26 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* struct retro_camera_callback * --
+ * Gets an interface to a video camera driver.
+ * A libretro core can use this interface to get access to a
+ * video camera.
+ * New video frames are delivered in a callback in same
+ * thread as retro_run().
+ *
+ * GET_CAMERA_INTERFACE should be called in retro_load_game().
+ *
+ * Depending on the camera implementation used, camera frames
+ * will be delivered as a raw framebuffer,
+ * or as an OpenGL texture directly.
+ *
+ * The core has to tell the frontend here which types of
+ * buffers can be handled properly.
+ * An OpenGL texture can only be handled when using a
+ * libretro GL core (SET_HW_RENDER).
+ * It is recommended to use a libretro GL core when
+ * using camera interface.
+ *
+ * The camera is not started automatically. The retrieved start/stop
+ * functions must be used to explicitly
+ * start and stop the camera driver.
+ */
+#define RETRO_ENVIRONMENT_GET_LOG_INTERFACE 27
+ /* struct retro_log_callback * --
+ * Gets an interface for logging. This is useful for
+ * logging in a cross-platform way
+ * as certain platforms cannot use stderr for logging.
+ * It also allows the frontend to
+ * show logging information in a more suitable way.
+ * If this interface is not used, libretro cores should
+ * log to stderr as desired.
+ */
+#define RETRO_ENVIRONMENT_GET_PERF_INTERFACE 28
+ /* struct retro_perf_callback * --
+ * Gets an interface for performance counters. This is useful
+ * for performance logging in a cross-platform way and for detecting
+ * architecture-specific features, such as SIMD support.
+ */
+#define RETRO_ENVIRONMENT_GET_LOCATION_INTERFACE 29
+ /* struct retro_location_callback * --
+ * Gets access to the location interface.
+ * The purpose of this interface is to be able to retrieve
+ * location-based information from the host device,
+ * such as current latitude / longitude.
+ */
+#define RETRO_ENVIRONMENT_GET_CONTENT_DIRECTORY 30 /* Old name, kept for compatibility. */
+#define RETRO_ENVIRONMENT_GET_CORE_ASSETS_DIRECTORY 30
+ /* const char ** --
+ * Returns the "core assets" directory of the frontend.
+ * This directory can be used to store specific assets that the
+ * core relies upon, such as art assets,
+ * input data, etc etc.
+ * The returned value can be NULL.
+ * If so, no such directory is defined,
+ * and it's up to the implementation to find a suitable directory.
+ */
+#define RETRO_ENVIRONMENT_GET_SAVE_DIRECTORY 31
+ /* const char ** --
+ * Returns the "save" directory of the frontend, unless there is no
+ * save directory available. The save directory should be used to
+ * store SRAM, memory cards, high scores, etc, if the libretro core
+ * cannot use the regular memory interface (retro_get_memory_data()).
+ *
+ * If the frontend cannot designate a save directory, it will return
+ * NULL to indicate that the core should attempt to operate without a
+ * save directory set.
+ *
+ * NOTE: early libretro cores used the system directory for save
+ * files. Cores that need to be backwards-compatible can still check
+ * GET_SYSTEM_DIRECTORY.
+ */
+#define RETRO_ENVIRONMENT_SET_SYSTEM_AV_INFO 32
+ /* const struct retro_system_av_info * --
+ * Sets a new av_info structure. This can only be called from
+ * within retro_run().
+ * This should *only* be used if the core is completely altering the
+ * internal resolutions, aspect ratios, timings, sampling rate, etc.
+ * Calling this can require a full reinitialization of video/audio
+ * drivers in the frontend,
+ *
+ * so it is important to call it very sparingly, and usually only with
+ * the users explicit consent.
+ * An eventual driver reinitialize will happen so that video and
+ * audio callbacks
+ * happening after this call within the same retro_run() call will
+ * target the newly initialized driver.
+ *
+ * This callback makes it possible to support configurable resolutions
+ * in games, which can be useful to
+ * avoid setting the "worst case" in max_width/max_height.
+ *
+ * ***HIGHLY RECOMMENDED*** Do not call this callback every time
+ * resolution changes in an emulator core if it's
+ * expected to be a temporary change, for the reasons of possible
+ * driver reinitialization.
+ * This call is not a free pass for not trying to provide
+ * correct values in retro_get_system_av_info(). If you need to change
+ * things like aspect ratio or nominal width/height,
+ * use RETRO_ENVIRONMENT_SET_GEOMETRY, which is a softer variant
+ * of SET_SYSTEM_AV_INFO.
+ *
+ * If this returns false, the frontend does not acknowledge a
+ * changed av_info struct.
+ */
+#define RETRO_ENVIRONMENT_SET_PROC_ADDRESS_CALLBACK 33
+ /* const struct retro_get_proc_address_interface * --
+ * Allows a libretro core to announce support for the
+ * get_proc_address() interface.
+ * This interface allows for a standard way to extend libretro where
+ * use of environment calls are too indirect,
+ * e.g. for cases where the frontend wants to call directly into the core.
+ *
+ * If a core wants to expose this interface, SET_PROC_ADDRESS_CALLBACK
+ * **MUST** be called from within retro_set_environment().
+ */
+#define RETRO_ENVIRONMENT_SET_SUBSYSTEM_INFO 34
+ /* const struct retro_subsystem_info * --
+ * This environment call introduces the concept of libretro "subsystems".
+ * A subsystem is a variant of a libretro core which supports
+ * different kinds of games.
+ * The purpose of this is to support e.g. emulators which might
+ * have special needs, e.g. Super Nintendo's Super GameBoy, Sufami Turbo.
+ * It can also be used to pick among subsystems in an explicit way
+ * if the libretro implementation is a multi-system emulator itself.
+ *
+ * Loading a game via a subsystem is done with retro_load_game_special(),
+ * and this environment call allows a libretro core to expose which
+ * subsystems are supported for use with retro_load_game_special().
+ * A core passes an array of retro_game_special_info which is terminated
+ * with a zeroed out retro_game_special_info struct.
+ *
+ * If a core wants to use this functionality, SET_SUBSYSTEM_INFO
+ * **MUST** be called from within retro_set_environment().
+ */
+#define RETRO_ENVIRONMENT_SET_CONTROLLER_INFO 35
+ /* const struct retro_controller_info * --
+ * This environment call lets a libretro core tell the frontend
+ * which controller subclasses are recognized in calls to
+ * retro_set_controller_port_device().
+ *
+ * Some emulators such as Super Nintendo support multiple lightgun
+ * types which must be specifically selected from. It is therefore
+ * sometimes necessary for a frontend to be able to tell the core
+ * about a special kind of input device which is not specifcally
+ * provided by the Libretro API.
+ *
+ * In order for a frontend to understand the workings of those devices,
+ * they must be defined as a specialized subclass of the generic device
+ * types already defined in the libretro API.
+ *
+ * The core must pass an array of const struct retro_controller_info which
+ * is terminated with a blanked out struct. Each element of the
+ * retro_controller_info struct corresponds to the ascending port index
+ * that is passed to retro_set_controller_port_device() when that function
+ * is called to indicate to the core that the frontend has changed the
+ * active device subclass. SEE ALSO: retro_set_controller_port_device()
+ *
+ * The ascending input port indexes provided by the core in the struct
+ * are generally presented by frontends as ascending User # or Player #,
+ * such as Player 1, Player 2, Player 3, etc. Which device subclasses are
+ * supported can vary per input port.
+ *
+ * The first inner element of each entry in the retro_controller_info array
+ * is a retro_controller_description struct that specifies the names and
+ * codes of all device subclasses that are available for the corresponding
+ * User or Player, beginning with the generic Libretro device that the
+ * subclasses are derived from. The second inner element of each entry is the
+ * total number of subclasses that are listed in the retro_controller_description.
+ *
+ * NOTE: Even if special device types are set in the libretro core,
+ * libretro should only poll input based on the base input device types.
+ */
+#define RETRO_ENVIRONMENT_SET_MEMORY_MAPS (36 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* const struct retro_memory_map * --
+ * This environment call lets a libretro core tell the frontend
+ * about the memory maps this core emulates.
+ * This can be used to implement, for example, cheats in a core-agnostic way.
+ *
+ * Should only be used by emulators; it doesn't make much sense for
+ * anything else.
+ * It is recommended to expose all relevant pointers through
+ * retro_get_memory_* as well.
+ *
+ * Can be called from retro_init and retro_load_game.
+ */
+#define RETRO_ENVIRONMENT_SET_GEOMETRY 37
+ /* const struct retro_game_geometry * --
+ * This environment call is similar to SET_SYSTEM_AV_INFO for changing
+ * video parameters, but provides a guarantee that drivers will not be
+ * reinitialized.
+ * This can only be called from within retro_run().
+ *
+ * The purpose of this call is to allow a core to alter nominal
+ * width/heights as well as aspect ratios on-the-fly, which can be
+ * useful for some emulators to change in run-time.
+ *
+ * max_width/max_height arguments are ignored and cannot be changed
+ * with this call as this could potentially require a reinitialization or a
+ * non-constant time operation.
+ * If max_width/max_height are to be changed, SET_SYSTEM_AV_INFO is required.
+ *
+ * A frontend must guarantee that this environment call completes in
+ * constant time.
+ */
+#define RETRO_ENVIRONMENT_GET_USERNAME 38
+ /* const char **
+ * Returns the specified username of the frontend, if specified by the user.
+ * This username can be used as a nickname for a core that has online facilities
+ * or any other mode where personalization of the user is desirable.
+ * The returned value can be NULL.
+ * If this environ callback is used by a core that requires a valid username,
+ * a default username should be specified by the core.
+ */
+#define RETRO_ENVIRONMENT_GET_LANGUAGE 39
+ /* unsigned * --
+ * Returns the specified language of the frontend, if specified by the user.
+ * It can be used by the core for localization purposes.
+ */
+#define RETRO_ENVIRONMENT_GET_CURRENT_SOFTWARE_FRAMEBUFFER (40 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* struct retro_framebuffer * --
+ * Returns a preallocated framebuffer which the core can use for rendering
+ * the frame into when not using SET_HW_RENDER.
+ * The framebuffer returned from this call must not be used
+ * after the current call to retro_run() returns.
+ *
+ * The goal of this call is to allow zero-copy behavior where a core
+ * can render directly into video memory, avoiding extra bandwidth cost by copying
+ * memory from core to video memory.
+ *
+ * If this call succeeds and the core renders into it,
+ * the framebuffer pointer and pitch can be passed to retro_video_refresh_t.
+ * If the buffer from GET_CURRENT_SOFTWARE_FRAMEBUFFER is to be used,
+ * the core must pass the exact
+ * same pointer as returned by GET_CURRENT_SOFTWARE_FRAMEBUFFER;
+ * i.e. passing a pointer which is offset from the
+ * buffer is undefined. The width, height and pitch parameters
+ * must also match exactly to the values obtained from GET_CURRENT_SOFTWARE_FRAMEBUFFER.
+ *
+ * It is possible for a frontend to return a different pixel format
+ * than the one used in SET_PIXEL_FORMAT. This can happen if the frontend
+ * needs to perform conversion.
+ *
+ * It is still valid for a core to render to a different buffer
+ * even if GET_CURRENT_SOFTWARE_FRAMEBUFFER succeeds.
+ *
+ * A frontend must make sure that the pointer obtained from this function is
+ * writeable (and readable).
+ */
+#define RETRO_ENVIRONMENT_GET_HW_RENDER_INTERFACE (41 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* const struct retro_hw_render_interface ** --
+ * Returns an API specific rendering interface for accessing API specific data.
+ * Not all HW rendering APIs support or need this.
+ * The contents of the returned pointer is specific to the rendering API
+ * being used. See the various headers like libretro_vulkan.h, etc.
+ *
+ * GET_HW_RENDER_INTERFACE cannot be called before context_reset has been called.
+ * Similarly, after context_destroyed callback returns,
+ * the contents of the HW_RENDER_INTERFACE are invalidated.
+ */
+#define RETRO_ENVIRONMENT_SET_SUPPORT_ACHIEVEMENTS (42 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* const bool * --
+ * If true, the libretro implementation supports achievements
+ * either via memory descriptors set with RETRO_ENVIRONMENT_SET_MEMORY_MAPS
+ * or via retro_get_memory_data/retro_get_memory_size.
+ *
+ * This must be called before the first call to retro_run.
+ */
+#define RETRO_ENVIRONMENT_SET_HW_RENDER_CONTEXT_NEGOTIATION_INTERFACE (43 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* const struct retro_hw_render_context_negotiation_interface * --
+ * Sets an interface which lets the libretro core negotiate with frontend how a context is created.
+ * The semantics of this interface depends on which API is used in SET_HW_RENDER earlier.
+ * This interface will be used when the frontend is trying to create a HW rendering context,
+ * so it will be used after SET_HW_RENDER, but before the context_reset callback.
+ */
+#define RETRO_ENVIRONMENT_SET_SERIALIZATION_QUIRKS 44
+ /* uint64_t * --
+ * Sets quirk flags associated with serialization. The frontend will zero any flags it doesn't
+ * recognize or support. Should be set in either retro_init or retro_load_game, but not both.
+ */
+#define RETRO_ENVIRONMENT_SET_HW_SHARED_CONTEXT (44 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* N/A (null) * --
+ * The frontend will try to use a 'shared' hardware context (mostly applicable
+ * to OpenGL) when a hardware context is being set up.
+ *
+ * Returns true if the frontend supports shared hardware contexts and false
+ * if the frontend does not support shared hardware contexts.
+ *
+ * This will do nothing on its own until SET_HW_RENDER env callbacks are
+ * being used.
+ */
+#define RETRO_ENVIRONMENT_GET_VFS_INTERFACE (45 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* struct retro_vfs_interface_info * --
+ * Gets access to the VFS interface.
+ * VFS presence needs to be queried prior to load_game or any
+ * get_system/save/other_directory being called to let front end know
+ * core supports VFS before it starts handing out paths.
+ * It is recomended to do so in retro_set_environment
+ */
+#define RETRO_ENVIRONMENT_GET_LED_INTERFACE (46 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* struct retro_led_interface * --
+ * Gets an interface which is used by a libretro core to set
+ * state of LEDs.
+ */
+#define RETRO_ENVIRONMENT_GET_AUDIO_VIDEO_ENABLE (47 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* int * --
+ * Tells the core if the frontend wants audio or video.
+ * If disabled, the frontend will discard the audio or video,
+ * so the core may decide to skip generating a frame or generating audio.
+ * This is mainly used for increasing performance.
+ * Bit 0 (value 1): Enable Video
+ * Bit 1 (value 2): Enable Audio
+ * Bit 2 (value 4): Use Fast Savestates.
+ * Bit 3 (value 8): Hard Disable Audio
+ * Other bits are reserved for future use and will default to zero.
+ * If video is disabled:
+ * * The frontend wants the core to not generate any video,
+ * including presenting frames via hardware acceleration.
+ * * The frontend's video frame callback will do nothing.
+ * * After running the frame, the video output of the next frame should be
+ * no different than if video was enabled, and saving and loading state
+ * should have no issues.
+ * If audio is disabled:
+ * * The frontend wants the core to not generate any audio.
+ * * The frontend's audio callbacks will do nothing.
+ * * After running the frame, the audio output of the next frame should be
+ * no different than if audio was enabled, and saving and loading state
+ * should have no issues.
+ * Fast Savestates:
+ * * Guaranteed to be created by the same binary that will load them.
+ * * Will not be written to or read from the disk.
+ * * Suggest that the core assumes loading state will succeed.
+ * * Suggest that the core updates its memory buffers in-place if possible.
+ * * Suggest that the core skips clearing memory.
+ * * Suggest that the core skips resetting the system.
+ * * Suggest that the core may skip validation steps.
+ * Hard Disable Audio:
+ * * Used for a secondary core when running ahead.
+ * * Indicates that the frontend will never need audio from the core.
+ * * Suggests that the core may stop synthesizing audio, but this should not
+ * compromise emulation accuracy.
+ * * Audio output for the next frame does not matter, and the frontend will
+ * never need an accurate audio state in the future.
+ * * State will never be saved when using Hard Disable Audio.
+ */
+#define RETRO_ENVIRONMENT_GET_MIDI_INTERFACE (48 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* struct retro_midi_interface ** --
+ * Returns a MIDI interface that can be used for raw data I/O.
+ */
+
+#define RETRO_ENVIRONMENT_GET_FASTFORWARDING (49 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* bool * --
+ * Boolean value that indicates whether or not the frontend is in
+ * fastforwarding mode.
+ */
+
+#define RETRO_ENVIRONMENT_GET_TARGET_REFRESH_RATE (50 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* float * --
+ * Float value that lets us know what target refresh rate
+ * is curently in use by the frontend.
+ *
+ * The core can use the returned value to set an ideal
+ * refresh rate/framerate.
+ */
+
+#define RETRO_ENVIRONMENT_GET_INPUT_BITMASKS (51 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+ /* bool * --
+ * Boolean value that indicates whether or not the frontend supports
+ * input bitmasks being returned by retro_input_state_t. The advantage
+ * of this is that retro_input_state_t has to be only called once to
+ * grab all button states instead of multiple times.
+ *
+ * If it returns true, you can pass RETRO_DEVICE_ID_JOYPAD_MASK as 'id'
+ * to retro_input_state_t (make sure 'device' is set to RETRO_DEVICE_JOYPAD).
+ * It will return a bitmask of all the digital buttons.
+ */
+
+#define RETRO_ENVIRONMENT_GET_CORE_OPTIONS_VERSION 52
+ /* unsigned * --
+ * Unsigned value is the API version number of the core options
+ * interface supported by the frontend. If callback return false,
+ * API version is assumed to be 0.
+ *
+ * In legacy code, core options are set by passing an array of
+ * retro_variable structs to RETRO_ENVIRONMENT_SET_VARIABLES.
+ * This may be still be done regardless of the core options
+ * interface version.
+ *
+ * If version is >= 1 however, core options may instead be set by
+ * passing an array of retro_core_option_definition structs to
+ * RETRO_ENVIRONMENT_SET_CORE_OPTIONS, or a 2D array of
+ * retro_core_option_definition structs to RETRO_ENVIRONMENT_SET_CORE_OPTIONS_INTL.
+ * This allows the core to additionally set option sublabel information
+ * and/or provide localisation support.
+ *
+ * If version is >= 2, core options may instead be set by passing
+ * a retro_core_options_v2 struct to RETRO_ENVIRONMENT_SET_CORE_OPTIONS_V2,
+ * or an array of retro_core_options_v2 structs to
+ * RETRO_ENVIRONMENT_SET_CORE_OPTIONS_V2_INTL. This allows the core
+ * to additionally set optional core option category information
+ * for frontends with core option category support.
+ */
+
+#define RETRO_ENVIRONMENT_SET_CORE_OPTIONS 53
+ /* const struct retro_core_option_definition ** --
+ * Allows an implementation to signal the environment
+ * which variables it might want to check for later using
+ * GET_VARIABLE.
+ * This allows the frontend to present these variables to
+ * a user dynamically.
+ * This should only be called if RETRO_ENVIRONMENT_GET_CORE_OPTIONS_VERSION
+ * returns an API version of >= 1.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_VARIABLES.
+ * This should be called the first time as early as
+ * possible (ideally in retro_set_environment).
+ * Afterwards it may be called again for the core to communicate
+ * updated options to the frontend, but the number of core
+ * options must not change from the number in the initial call.
+ *
+ * 'data' points to an array of retro_core_option_definition structs
+ * terminated by a { NULL, NULL, NULL, {{0}}, NULL } element.
+ * retro_core_option_definition::key should be namespaced to not collide
+ * with other implementations' keys. e.g. A core called
+ * 'foo' should use keys named as 'foo_option'.
+ * retro_core_option_definition::desc should contain a human readable
+ * description of the key.
+ * retro_core_option_definition::info should contain any additional human
+ * readable information text that a typical user may need to
+ * understand the functionality of the option.
+ * retro_core_option_definition::values is an array of retro_core_option_value
+ * structs terminated by a { NULL, NULL } element.
+ * > retro_core_option_definition::values[index].value is an expected option
+ * value.
+ * > retro_core_option_definition::values[index].label is a human readable
+ * label used when displaying the value on screen. If NULL,
+ * the value itself is used.
+ * retro_core_option_definition::default_value is the default core option
+ * setting. It must match one of the expected option values in the
+ * retro_core_option_definition::values array. If it does not, or the
+ * default value is NULL, the first entry in the
+ * retro_core_option_definition::values array is treated as the default.
+ *
+ * The number of possible option values should be very limited,
+ * and must be less than RETRO_NUM_CORE_OPTION_VALUES_MAX.
+ * i.e. it should be feasible to cycle through options
+ * without a keyboard.
+ *
+ * Example entry:
+ * {
+ * "foo_option",
+ * "Speed hack coprocessor X",
+ * "Provides increased performance at the expense of reduced accuracy",
+ * {
+ * { "false", NULL },
+ * { "true", NULL },
+ * { "unstable", "Turbo (Unstable)" },
+ * { NULL, NULL },
+ * },
+ * "false"
+ * }
+ *
+ * Only strings are operated on. The possible values will
+ * generally be displayed and stored as-is by the frontend.
+ */
+
+#define RETRO_ENVIRONMENT_SET_CORE_OPTIONS_INTL 54
+ /* const struct retro_core_options_intl * --
+ * Allows an implementation to signal the environment
+ * which variables it might want to check for later using
+ * GET_VARIABLE.
+ * This allows the frontend to present these variables to
+ * a user dynamically.
+ * This should only be called if RETRO_ENVIRONMENT_GET_CORE_OPTIONS_VERSION
+ * returns an API version of >= 1.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_VARIABLES.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_CORE_OPTIONS.
+ * This should be called the first time as early as
+ * possible (ideally in retro_set_environment).
+ * Afterwards it may be called again for the core to communicate
+ * updated options to the frontend, but the number of core
+ * options must not change from the number in the initial call.
+ *
+ * This is fundamentally the same as RETRO_ENVIRONMENT_SET_CORE_OPTIONS,
+ * with the addition of localisation support. The description of the
+ * RETRO_ENVIRONMENT_SET_CORE_OPTIONS callback should be consulted
+ * for further details.
+ *
+ * 'data' points to a retro_core_options_intl struct.
+ *
+ * retro_core_options_intl::us is a pointer to an array of
+ * retro_core_option_definition structs defining the US English
+ * core options implementation. It must point to a valid array.
+ *
+ * retro_core_options_intl::local is a pointer to an array of
+ * retro_core_option_definition structs defining core options for
+ * the current frontend language. It may be NULL (in which case
+ * retro_core_options_intl::us is used by the frontend). Any items
+ * missing from this array will be read from retro_core_options_intl::us
+ * instead.
+ *
+ * NOTE: Default core option values are always taken from the
+ * retro_core_options_intl::us array. Any default values in
+ * retro_core_options_intl::local array will be ignored.
+ */
+
+#define RETRO_ENVIRONMENT_SET_CORE_OPTIONS_DISPLAY 55
+ /* struct retro_core_option_display * --
+ *
+ * Allows an implementation to signal the environment to show
+ * or hide a variable when displaying core options. This is
+ * considered a *suggestion*. The frontend is free to ignore
+ * this callback, and its implementation not considered mandatory.
+ *
+ * 'data' points to a retro_core_option_display struct
+ *
+ * retro_core_option_display::key is a variable identifier
+ * which has already been set by SET_VARIABLES/SET_CORE_OPTIONS.
+ *
+ * retro_core_option_display::visible is a boolean, specifying
+ * whether variable should be displayed
+ *
+ * Note that all core option variables will be set visible by
+ * default when calling SET_VARIABLES/SET_CORE_OPTIONS.
+ */
+
+#define RETRO_ENVIRONMENT_GET_PREFERRED_HW_RENDER 56
+ /* unsigned * --
+ *
+ * Allows an implementation to ask frontend preferred hardware
+ * context to use. Core should use this information to deal
+ * with what specific context to request with SET_HW_RENDER.
+ *
+ * 'data' points to an unsigned variable
+ */
+
+#define RETRO_ENVIRONMENT_GET_DISK_CONTROL_INTERFACE_VERSION 57
+ /* unsigned * --
+ * Unsigned value is the API version number of the disk control
+ * interface supported by the frontend. If callback return false,
+ * API version is assumed to be 0.
+ *
+ * In legacy code, the disk control interface is defined by passing
+ * a struct of type retro_disk_control_callback to
+ * RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE.
+ * This may be still be done regardless of the disk control
+ * interface version.
+ *
+ * If version is >= 1 however, the disk control interface may
+ * instead be defined by passing a struct of type
+ * retro_disk_control_ext_callback to
+ * RETRO_ENVIRONMENT_SET_DISK_CONTROL_EXT_INTERFACE.
+ * This allows the core to provide additional information about
+ * disk images to the frontend and/or enables extra
+ * disk control functionality by the frontend.
+ */
+
+#define RETRO_ENVIRONMENT_SET_DISK_CONTROL_EXT_INTERFACE 58
+ /* const struct retro_disk_control_ext_callback * --
+ * Sets an interface which frontend can use to eject and insert
+ * disk images, and also obtain information about individual
+ * disk image files registered by the core.
+ * This is used for games which consist of multiple images and
+ * must be manually swapped out by the user (e.g. PSX, floppy disk
+ * based systems).
+ */
+
+#define RETRO_ENVIRONMENT_GET_MESSAGE_INTERFACE_VERSION 59
+ /* unsigned * --
+ * Unsigned value is the API version number of the message
+ * interface supported by the frontend. If callback returns
+ * false, API version is assumed to be 0.
+ *
+ * In legacy code, messages may be displayed in an
+ * implementation-specific manner by passing a struct
+ * of type retro_message to RETRO_ENVIRONMENT_SET_MESSAGE.
+ * This may be still be done regardless of the message
+ * interface version.
+ *
+ * If version is >= 1 however, messages may instead be
+ * displayed by passing a struct of type retro_message_ext
+ * to RETRO_ENVIRONMENT_SET_MESSAGE_EXT. This allows the
+ * core to specify message logging level, priority and
+ * destination (OSD, logging interface or both).
+ */
+
+#define RETRO_ENVIRONMENT_SET_MESSAGE_EXT 60
+ /* const struct retro_message_ext * --
+ * Sets a message to be displayed in an implementation-specific
+ * manner for a certain amount of 'frames'. Additionally allows
+ * the core to specify message logging level, priority and
+ * destination (OSD, logging interface or both).
+ * Should not be used for trivial messages, which should simply be
+ * logged via RETRO_ENVIRONMENT_GET_LOG_INTERFACE (or as a
+ * fallback, stderr).
+ */
+
+#define RETRO_ENVIRONMENT_GET_INPUT_MAX_USERS 61
+ /* unsigned * --
+ * Unsigned value is the number of active input devices
+ * provided by the frontend. This may change between
+ * frames, but will remain constant for the duration
+ * of each frame.
+ * If callback returns true, a core need not poll any
+ * input device with an index greater than or equal to
+ * the number of active devices.
+ * If callback returns false, the number of active input
+ * devices is unknown. In this case, all input devices
+ * should be considered active.
+ */
+
+#define RETRO_ENVIRONMENT_SET_AUDIO_BUFFER_STATUS_CALLBACK 62
+ /* const struct retro_audio_buffer_status_callback * --
+ * Lets the core know the occupancy level of the frontend
+ * audio buffer. Can be used by a core to attempt frame
+ * skipping in order to avoid buffer under-runs.
+ * A core may pass NULL to disable buffer status reporting
+ * in the frontend.
+ */
+
+#define RETRO_ENVIRONMENT_SET_MINIMUM_AUDIO_LATENCY 63
+ /* const unsigned * --
+ * Sets minimum frontend audio latency in milliseconds.
+ * Resultant audio latency may be larger than set value,
+ * or smaller if a hardware limit is encountered. A frontend
+ * is expected to honour requests up to 512 ms.
+ *
+ * - If value is less than current frontend
+ * audio latency, callback has no effect
+ * - If value is zero, default frontend audio
+ * latency is set
+ *
+ * May be used by a core to increase audio latency and
+ * therefore decrease the probability of buffer under-runs
+ * (crackling) when performing 'intensive' operations.
+ * A core utilising RETRO_ENVIRONMENT_SET_AUDIO_BUFFER_STATUS_CALLBACK
+ * to implement audio-buffer-based frame skipping may achieve
+ * optimal results by setting the audio latency to a 'high'
+ * (typically 6x or 8x) integer multiple of the expected
+ * frame time.
+ *
+ * WARNING: This can only be called from within retro_run().
+ * Calling this can require a full reinitialization of audio
+ * drivers in the frontend, so it is important to call it very
+ * sparingly, and usually only with the users explicit consent.
+ * An eventual driver reinitialize will happen so that audio
+ * callbacks happening after this call within the same retro_run()
+ * call will target the newly initialized driver.
+ */
+
+#define RETRO_ENVIRONMENT_SET_FASTFORWARDING_OVERRIDE 64
+ /* const struct retro_fastforwarding_override * --
+ * Used by a libretro core to override the current
+ * fastforwarding mode of the frontend.
+ * If NULL is passed to this function, the frontend
+ * will return true if fastforwarding override
+ * functionality is supported (no change in
+ * fastforwarding state will occur in this case).
+ */
+
+#define RETRO_ENVIRONMENT_SET_CONTENT_INFO_OVERRIDE 65
+ /* const struct retro_system_content_info_override * --
+ * Allows an implementation to override 'global' content
+ * info parameters reported by retro_get_system_info().
+ * Overrides also affect subsystem content info parameters
+ * set via RETRO_ENVIRONMENT_SET_SUBSYSTEM_INFO.
+ * This function must be called inside retro_set_environment().
+ * If callback returns false, content info overrides
+ * are unsupported by the frontend, and will be ignored.
+ * If callback returns true, extended game info may be
+ * retrieved by calling RETRO_ENVIRONMENT_GET_GAME_INFO_EXT
+ * in retro_load_game() or retro_load_game_special().
+ *
+ * 'data' points to an array of retro_system_content_info_override
+ * structs terminated by a { NULL, false, false } element.
+ * If 'data' is NULL, no changes will be made to the frontend;
+ * a core may therefore pass NULL in order to test whether
+ * the RETRO_ENVIRONMENT_SET_CONTENT_INFO_OVERRIDE and
+ * RETRO_ENVIRONMENT_GET_GAME_INFO_EXT callbacks are supported
+ * by the frontend.
+ *
+ * For struct member descriptions, see the definition of
+ * struct retro_system_content_info_override.
+ *
+ * Example:
+ *
+ * - struct retro_system_info:
+ * {
+ * "My Core", // library_name
+ * "v1.0", // library_version
+ * "m3u|md|cue|iso|chd|sms|gg|sg", // valid_extensions
+ * true, // need_fullpath
+ * false // block_extract
+ * }
+ *
+ * - Array of struct retro_system_content_info_override:
+ * {
+ * {
+ * "md|sms|gg", // extensions
+ * false, // need_fullpath
+ * true // persistent_data
+ * },
+ * {
+ * "sg", // extensions
+ * false, // need_fullpath
+ * false // persistent_data
+ * },
+ * { NULL, false, false }
+ * }
+ *
+ * Result:
+ * - Files of type m3u, cue, iso, chd will not be
+ * loaded by the frontend. Frontend will pass a
+ * valid path to the core, and core will handle
+ * loading internally
+ * - Files of type md, sms, gg will be loaded by
+ * the frontend. A valid memory buffer will be
+ * passed to the core. This memory buffer will
+ * remain valid until retro_deinit() returns
+ * - Files of type sg will be loaded by the frontend.
+ * A valid memory buffer will be passed to the core.
+ * This memory buffer will remain valid until
+ * retro_load_game() (or retro_load_game_special())
+ * returns
+ *
+ * NOTE: If an extension is listed multiple times in
+ * an array of retro_system_content_info_override
+ * structs, only the first instance will be registered
+ */
+
+#define RETRO_ENVIRONMENT_GET_GAME_INFO_EXT 66
+ /* const struct retro_game_info_ext ** --
+ * Allows an implementation to fetch extended game
+ * information, providing additional content path
+ * and memory buffer status details.
+ * This function may only be called inside
+ * retro_load_game() or retro_load_game_special().
+ * If callback returns false, extended game information
+ * is unsupported by the frontend. In this case, only
+ * regular retro_game_info will be available.
+ * RETRO_ENVIRONMENT_GET_GAME_INFO_EXT is guaranteed
+ * to return true if RETRO_ENVIRONMENT_SET_CONTENT_INFO_OVERRIDE
+ * returns true.
+ *
+ * 'data' points to an array of retro_game_info_ext structs.
+ *
+ * For struct member descriptions, see the definition of
+ * struct retro_game_info_ext.
+ *
+ * - If function is called inside retro_load_game(),
+ * the retro_game_info_ext array is guaranteed to
+ * have a size of 1 - i.e. the returned pointer may
+ * be used to access directly the members of the
+ * first retro_game_info_ext struct, for example:
+ *
+ * struct retro_game_info_ext *game_info_ext;
+ * if (environ_cb(RETRO_ENVIRONMENT_GET_GAME_INFO_EXT, &game_info_ext))
+ * printf("Content Directory: %s\n", game_info_ext->dir);
+ *
+ * - If the function is called inside retro_load_game_special(),
+ * the retro_game_info_ext array is guaranteed to have a
+ * size equal to the num_info argument passed to
+ * retro_load_game_special()
+ */
+
+#define RETRO_ENVIRONMENT_SET_CORE_OPTIONS_V2 67
+ /* const struct retro_core_options_v2 * --
+ * Allows an implementation to signal the environment
+ * which variables it might want to check for later using
+ * GET_VARIABLE.
+ * This allows the frontend to present these variables to
+ * a user dynamically.
+ * This should only be called if RETRO_ENVIRONMENT_GET_CORE_OPTIONS_VERSION
+ * returns an API version of >= 2.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_VARIABLES.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_CORE_OPTIONS.
+ * This should be called the first time as early as
+ * possible (ideally in retro_set_environment).
+ * Afterwards it may be called again for the core to communicate
+ * updated options to the frontend, but the number of core
+ * options must not change from the number in the initial call.
+ * If RETRO_ENVIRONMENT_GET_CORE_OPTIONS_VERSION returns an API
+ * version of >= 2, this callback is guaranteed to succeed
+ * (i.e. callback return value does not indicate success)
+ * If callback returns true, frontend has core option category
+ * support.
+ * If callback returns false, frontend does not have core option
+ * category support.
+ *
+ * 'data' points to a retro_core_options_v2 struct, containing
+ * of two pointers:
+ * - retro_core_options_v2::categories is an array of
+ * retro_core_option_v2_category structs terminated by a
+ * { NULL, NULL, NULL } element. If retro_core_options_v2::categories
+ * is NULL, all core options will have no category and will be shown
+ * at the top level of the frontend core option interface. If frontend
+ * does not have core option category support, categories array will
+ * be ignored.
+ * - retro_core_options_v2::definitions is an array of
+ * retro_core_option_v2_definition structs terminated by a
+ * { NULL, NULL, NULL, NULL, NULL, NULL, {{0}}, NULL }
+ * element.
+ *
+ * >> retro_core_option_v2_category notes:
+ *
+ * - retro_core_option_v2_category::key should contain string
+ * that uniquely identifies the core option category. Valid
+ * key characters are [a-z, A-Z, 0-9, _, -]
+ * Namespace collisions with other implementations' category
+ * keys are permitted.
+ * - retro_core_option_v2_category::desc should contain a human
+ * readable description of the category key.
+ * - retro_core_option_v2_category::info should contain any
+ * additional human readable information text that a typical
+ * user may need to understand the nature of the core option
+ * category.
+ *
+ * Example entry:
+ * {
+ * "advanced_settings",
+ * "Advanced",
+ * "Options affecting low-level emulation performance and accuracy."
+ * }
+ *
+ * >> retro_core_option_v2_definition notes:
+ *
+ * - retro_core_option_v2_definition::key should be namespaced to not
+ * collide with other implementations' keys. e.g. A core called
+ * 'foo' should use keys named as 'foo_option'. Valid key characters
+ * are [a-z, A-Z, 0-9, _, -].
+ * - retro_core_option_v2_definition::desc should contain a human readable
+ * description of the key. Will be used when the frontend does not
+ * have core option category support. Examples: "Aspect Ratio" or
+ * "Video > Aspect Ratio".
+ * - retro_core_option_v2_definition::desc_categorized should contain a
+ * human readable description of the key, which will be used when
+ * frontend has core option category support. Example: "Aspect Ratio",
+ * where associated retro_core_option_v2_category::desc is "Video".
+ * If empty or NULL, the string specified by
+ * retro_core_option_v2_definition::desc will be used instead.
+ * retro_core_option_v2_definition::desc_categorized will be ignored
+ * if retro_core_option_v2_definition::category_key is empty or NULL.
+ * - retro_core_option_v2_definition::info should contain any additional
+ * human readable information text that a typical user may need to
+ * understand the functionality of the option.
+ * - retro_core_option_v2_definition::info_categorized should contain
+ * any additional human readable information text that a typical user
+ * may need to understand the functionality of the option, and will be
+ * used when frontend has core option category support. This is provided
+ * to accommodate the case where info text references an option by
+ * name/desc, and the desc/desc_categorized text for that option differ.
+ * If empty or NULL, the string specified by
+ * retro_core_option_v2_definition::info will be used instead.
+ * retro_core_option_v2_definition::info_categorized will be ignored
+ * if retro_core_option_v2_definition::category_key is empty or NULL.
+ * - retro_core_option_v2_definition::category_key should contain a
+ * category identifier (e.g. "video" or "audio") that will be
+ * assigned to the core option if frontend has core option category
+ * support. A categorized option will be shown in a subsection/
+ * submenu of the frontend core option interface. If key is empty
+ * or NULL, or if key does not match one of the
+ * retro_core_option_v2_category::key values in the associated
+ * retro_core_option_v2_category array, option will have no category
+ * and will be shown at the top level of the frontend core option
+ * interface.
+ * - retro_core_option_v2_definition::values is an array of
+ * retro_core_option_value structs terminated by a { NULL, NULL }
+ * element.
+ * --> retro_core_option_v2_definition::values[index].value is an
+ * expected option value.
+ * --> retro_core_option_v2_definition::values[index].label is a
+ * human readable label used when displaying the value on screen.
+ * If NULL, the value itself is used.
+ * - retro_core_option_v2_definition::default_value is the default
+ * core option setting. It must match one of the expected option
+ * values in the retro_core_option_v2_definition::values array. If
+ * it does not, or the default value is NULL, the first entry in the
+ * retro_core_option_v2_definition::values array is treated as the
+ * default.
+ *
+ * The number of possible option values should be very limited,
+ * and must be less than RETRO_NUM_CORE_OPTION_VALUES_MAX.
+ * i.e. it should be feasible to cycle through options
+ * without a keyboard.
+ *
+ * Example entries:
+ *
+ * - Uncategorized:
+ *
+ * {
+ * "foo_option",
+ * "Speed hack coprocessor X",
+ * NULL,
+ * "Provides increased performance at the expense of reduced accuracy.",
+ * NULL,
+ * NULL,
+ * {
+ * { "false", NULL },
+ * { "true", NULL },
+ * { "unstable", "Turbo (Unstable)" },
+ * { NULL, NULL },
+ * },
+ * "false"
+ * }
+ *
+ * - Categorized:
+ *
+ * {
+ * "foo_option",
+ * "Advanced > Speed hack coprocessor X",
+ * "Speed hack coprocessor X",
+ * "Setting 'Advanced > Speed hack coprocessor X' to 'true' or 'Turbo' provides increased performance at the expense of reduced accuracy",
+ * "Setting 'Speed hack coprocessor X' to 'true' or 'Turbo' provides increased performance at the expense of reduced accuracy",
+ * "advanced_settings",
+ * {
+ * { "false", NULL },
+ * { "true", NULL },
+ * { "unstable", "Turbo (Unstable)" },
+ * { NULL, NULL },
+ * },
+ * "false"
+ * }
+ *
+ * Only strings are operated on. The possible values will
+ * generally be displayed and stored as-is by the frontend.
+ */
+
+#define RETRO_ENVIRONMENT_SET_CORE_OPTIONS_V2_INTL 68
+ /* const struct retro_core_options_v2_intl * --
+ * Allows an implementation to signal the environment
+ * which variables it might want to check for later using
+ * GET_VARIABLE.
+ * This allows the frontend to present these variables to
+ * a user dynamically.
+ * This should only be called if RETRO_ENVIRONMENT_GET_CORE_OPTIONS_VERSION
+ * returns an API version of >= 2.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_VARIABLES.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_CORE_OPTIONS.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_CORE_OPTIONS_INTL.
+ * This should be called instead of RETRO_ENVIRONMENT_SET_CORE_OPTIONS_V2.
+ * This should be called the first time as early as
+ * possible (ideally in retro_set_environment).
+ * Afterwards it may be called again for the core to communicate
+ * updated options to the frontend, but the number of core
+ * options must not change from the number in the initial call.
+ * If RETRO_ENVIRONMENT_GET_CORE_OPTIONS_VERSION returns an API
+ * version of >= 2, this callback is guaranteed to succeed
+ * (i.e. callback return value does not indicate success)
+ * If callback returns true, frontend has core option category
+ * support.
+ * If callback returns false, frontend does not have core option
+ * category support.
+ *
+ * This is fundamentally the same as RETRO_ENVIRONMENT_SET_CORE_OPTIONS_V2,
+ * with the addition of localisation support. The description of the
+ * RETRO_ENVIRONMENT_SET_CORE_OPTIONS_V2 callback should be consulted
+ * for further details.
+ *
+ * 'data' points to a retro_core_options_v2_intl struct.
+ *
+ * - retro_core_options_v2_intl::us is a pointer to a
+ * retro_core_options_v2 struct defining the US English
+ * core options implementation. It must point to a valid struct.
+ *
+ * - retro_core_options_v2_intl::local is a pointer to a
+ * retro_core_options_v2 struct defining core options for
+ * the current frontend language. It may be NULL (in which case
+ * retro_core_options_v2_intl::us is used by the frontend). Any items
+ * missing from this struct will be read from
+ * retro_core_options_v2_intl::us instead.
+ *
+ * NOTE: Default core option values are always taken from the
+ * retro_core_options_v2_intl::us struct. Any default values in
+ * the retro_core_options_v2_intl::local struct will be ignored.
+ */
+
+#define RETRO_ENVIRONMENT_SET_CORE_OPTIONS_UPDATE_DISPLAY_CALLBACK 69
+ /* const struct retro_core_options_update_display_callback * --
+ * Allows a frontend to signal that a core must update
+ * the visibility of any dynamically hidden core options,
+ * and enables the frontend to detect visibility changes.
+ * Used by the frontend to update the menu display status
+ * of core options without requiring a call of retro_run().
+ * Must be called in retro_set_environment().
+ */
+
+/* VFS functionality */
+
+/* File paths:
+ * File paths passed as parameters when using this API shall be well formed UNIX-style,
+ * using "/" (unquoted forward slash) as directory separator regardless of the platform's native separator.
+ * Paths shall also include at least one forward slash ("game.bin" is an invalid path, use "./game.bin" instead).
+ * Other than the directory separator, cores shall not make assumptions about path format:
+ * "C:/path/game.bin", "http://example.com/game.bin", "#game/game.bin", "./game.bin" (without quotes) are all valid paths.
+ * Cores may replace the basename or remove path components from the end, and/or add new components;
+ * however, cores shall not append "./", "../" or multiple consecutive forward slashes ("//") to paths they request to front end.
+ * The frontend is encouraged to make such paths work as well as it can, but is allowed to give up if the core alters paths too much.
+ * Frontends are encouraged, but not required, to support native file system paths (modulo replacing the directory separator, if applicable).
+ * Cores are allowed to try using them, but must remain functional if the front rejects such requests.
+ * Cores are encouraged to use the libretro-common filestream functions for file I/O,
+ * as they seamlessly integrate with VFS, deal with directory separator replacement as appropriate
+ * and provide platform-specific fallbacks in cases where front ends do not support VFS. */
+
+/* Opaque file handle
+ * Introduced in VFS API v1 */
+struct retro_vfs_file_handle;
+
+/* Opaque directory handle
+ * Introduced in VFS API v3 */
+struct retro_vfs_dir_handle;
+
+/* File open flags
+ * Introduced in VFS API v1 */
+#define RETRO_VFS_FILE_ACCESS_READ (1 << 0) /* Read only mode */
+#define RETRO_VFS_FILE_ACCESS_WRITE (1 << 1) /* Write only mode, discard contents and overwrites existing file unless RETRO_VFS_FILE_ACCESS_UPDATE is also specified */
+#define RETRO_VFS_FILE_ACCESS_READ_WRITE (RETRO_VFS_FILE_ACCESS_READ | RETRO_VFS_FILE_ACCESS_WRITE) /* Read-write mode, discard contents and overwrites existing file unless RETRO_VFS_FILE_ACCESS_UPDATE is also specified*/
+#define RETRO_VFS_FILE_ACCESS_UPDATE_EXISTING (1 << 2) /* Prevents discarding content of existing files opened for writing */
+
+/* These are only hints. The frontend may choose to ignore them. Other than RAM/CPU/etc use,
+ and how they react to unlikely external interference (for example someone else writing to that file,
+ or the file's server going down), behavior will not change. */
+#define RETRO_VFS_FILE_ACCESS_HINT_NONE (0)
+/* Indicate that the file will be accessed many times. The frontend should aggressively cache everything. */
+#define RETRO_VFS_FILE_ACCESS_HINT_FREQUENT_ACCESS (1 << 0)
+
+/* Seek positions */
+#define RETRO_VFS_SEEK_POSITION_START 0
+#define RETRO_VFS_SEEK_POSITION_CURRENT 1
+#define RETRO_VFS_SEEK_POSITION_END 2
+
+/* stat() result flags
+ * Introduced in VFS API v3 */
+#define RETRO_VFS_STAT_IS_VALID (1 << 0)
+#define RETRO_VFS_STAT_IS_DIRECTORY (1 << 1)
+#define RETRO_VFS_STAT_IS_CHARACTER_SPECIAL (1 << 2)
+
+/* Get path from opaque handle. Returns the exact same path passed to file_open when getting the handle
+ * Introduced in VFS API v1 */
+typedef const char *(RETRO_CALLCONV *retro_vfs_get_path_t)(struct retro_vfs_file_handle *stream);
+
+/* Open a file for reading or writing. If path points to a directory, this will
+ * fail. Returns the opaque file handle, or NULL for error.
+ * Introduced in VFS API v1 */
+typedef struct retro_vfs_file_handle *(RETRO_CALLCONV *retro_vfs_open_t)(const char *path, unsigned mode, unsigned hints);
+
+/* Close the file and release its resources. Must be called if open_file returns non-NULL. Returns 0 on success, -1 on failure.
+ * Whether the call succeeds ot not, the handle passed as parameter becomes invalid and should no longer be used.
+ * Introduced in VFS API v1 */
+typedef int (RETRO_CALLCONV *retro_vfs_close_t)(struct retro_vfs_file_handle *stream);
+
+/* Return the size of the file in bytes, or -1 for error.
+ * Introduced in VFS API v1 */
+typedef int64_t (RETRO_CALLCONV *retro_vfs_size_t)(struct retro_vfs_file_handle *stream);
+
+/* Truncate file to specified size. Returns 0 on success or -1 on error
+ * Introduced in VFS API v2 */
+typedef int64_t (RETRO_CALLCONV *retro_vfs_truncate_t)(struct retro_vfs_file_handle *stream, int64_t length);
+
+/* Get the current read / write position for the file. Returns -1 for error.
+ * Introduced in VFS API v1 */
+typedef int64_t (RETRO_CALLCONV *retro_vfs_tell_t)(struct retro_vfs_file_handle *stream);
+
+/* Set the current read/write position for the file. Returns the new position, -1 for error.
+ * Introduced in VFS API v1 */
+typedef int64_t (RETRO_CALLCONV *retro_vfs_seek_t)(struct retro_vfs_file_handle *stream, int64_t offset, int seek_position);
+
+/* Read data from a file. Returns the number of bytes read, or -1 for error.
+ * Introduced in VFS API v1 */
+typedef int64_t (RETRO_CALLCONV *retro_vfs_read_t)(struct retro_vfs_file_handle *stream, void *s, uint64_t len);
+
+/* Write data to a file. Returns the number of bytes written, or -1 for error.
+ * Introduced in VFS API v1 */
+typedef int64_t (RETRO_CALLCONV *retro_vfs_write_t)(struct retro_vfs_file_handle *stream, const void *s, uint64_t len);
+
+/* Flush pending writes to file, if using buffered IO. Returns 0 on sucess, or -1 on failure.
+ * Introduced in VFS API v1 */
+typedef int (RETRO_CALLCONV *retro_vfs_flush_t)(struct retro_vfs_file_handle *stream);
+
+/* Delete the specified file. Returns 0 on success, -1 on failure
+ * Introduced in VFS API v1 */
+typedef int (RETRO_CALLCONV *retro_vfs_remove_t)(const char *path);
+
+/* Rename the specified file. Returns 0 on success, -1 on failure
+ * Introduced in VFS API v1 */
+typedef int (RETRO_CALLCONV *retro_vfs_rename_t)(const char *old_path, const char *new_path);
+
+/* Stat the specified file. Retruns a bitmask of RETRO_VFS_STAT_* flags, none are set if path was not valid.
+ * Additionally stores file size in given variable, unless NULL is given.
+ * Introduced in VFS API v3 */
+typedef int (RETRO_CALLCONV *retro_vfs_stat_t)(const char *path, int32_t *size);
+
+/* Create the specified directory. Returns 0 on success, -1 on unknown failure, -2 if already exists.
+ * Introduced in VFS API v3 */
+typedef int (RETRO_CALLCONV *retro_vfs_mkdir_t)(const char *dir);
+
+/* Open the specified directory for listing. Returns the opaque dir handle, or NULL for error.
+ * Support for the include_hidden argument may vary depending on the platform.
+ * Introduced in VFS API v3 */
+typedef struct retro_vfs_dir_handle *(RETRO_CALLCONV *retro_vfs_opendir_t)(const char *dir, bool include_hidden);
+
+/* Read the directory entry at the current position, and move the read pointer to the next position.
+ * Returns true on success, false if already on the last entry.
+ * Introduced in VFS API v3 */
+typedef bool (RETRO_CALLCONV *retro_vfs_readdir_t)(struct retro_vfs_dir_handle *dirstream);
+
+/* Get the name of the last entry read. Returns a string on success, or NULL for error.
+ * The returned string pointer is valid until the next call to readdir or closedir.
+ * Introduced in VFS API v3 */
+typedef const char *(RETRO_CALLCONV *retro_vfs_dirent_get_name_t)(struct retro_vfs_dir_handle *dirstream);
+
+/* Check if the last entry read was a directory. Returns true if it was, false otherwise (or on error).
+ * Introduced in VFS API v3 */
+typedef bool (RETRO_CALLCONV *retro_vfs_dirent_is_dir_t)(struct retro_vfs_dir_handle *dirstream);
+
+/* Close the directory and release its resources. Must be called if opendir returns non-NULL. Returns 0 on success, -1 on failure.
+ * Whether the call succeeds ot not, the handle passed as parameter becomes invalid and should no longer be used.
+ * Introduced in VFS API v3 */
+typedef int (RETRO_CALLCONV *retro_vfs_closedir_t)(struct retro_vfs_dir_handle *dirstream);
+
+struct retro_vfs_interface
+{
+ /* VFS API v1 */
+ retro_vfs_get_path_t get_path;
+ retro_vfs_open_t open;
+ retro_vfs_close_t close;
+ retro_vfs_size_t size;
+ retro_vfs_tell_t tell;
+ retro_vfs_seek_t seek;
+ retro_vfs_read_t read;
+ retro_vfs_write_t write;
+ retro_vfs_flush_t flush;
+ retro_vfs_remove_t remove;
+ retro_vfs_rename_t rename;
+ /* VFS API v2 */
+ retro_vfs_truncate_t truncate;
+ /* VFS API v3 */
+ retro_vfs_stat_t stat;
+ retro_vfs_mkdir_t mkdir;
+ retro_vfs_opendir_t opendir;
+ retro_vfs_readdir_t readdir;
+ retro_vfs_dirent_get_name_t dirent_get_name;
+ retro_vfs_dirent_is_dir_t dirent_is_dir;
+ retro_vfs_closedir_t closedir;
+};
+
+struct retro_vfs_interface_info
+{
+ /* Set by core: should this be higher than the version the front end supports,
+ * front end will return false in the RETRO_ENVIRONMENT_GET_VFS_INTERFACE call
+ * Introduced in VFS API v1 */
+ uint32_t required_interface_version;
+
+ /* Frontend writes interface pointer here. The frontend also sets the actual
+ * version, must be at least required_interface_version.
+ * Introduced in VFS API v1 */
+ struct retro_vfs_interface *iface;
+};
+
+enum retro_hw_render_interface_type
+{
+ RETRO_HW_RENDER_INTERFACE_VULKAN = 0,
+ RETRO_HW_RENDER_INTERFACE_D3D9 = 1,
+ RETRO_HW_RENDER_INTERFACE_D3D10 = 2,
+ RETRO_HW_RENDER_INTERFACE_D3D11 = 3,
+ RETRO_HW_RENDER_INTERFACE_D3D12 = 4,
+ RETRO_HW_RENDER_INTERFACE_GSKIT_PS2 = 5,
+ RETRO_HW_RENDER_INTERFACE_DUMMY = INT_MAX
+};
+
+/* Base struct. All retro_hw_render_interface_* types
+ * contain at least these fields. */
+struct retro_hw_render_interface
+{
+ enum retro_hw_render_interface_type interface_type;
+ unsigned interface_version;
+};
+
+typedef void (RETRO_CALLCONV *retro_set_led_state_t)(int led, int state);
+struct retro_led_interface
+{
+ retro_set_led_state_t set_led_state;
+};
+
+/* Retrieves the current state of the MIDI input.
+ * Returns true if it's enabled, false otherwise. */
+typedef bool (RETRO_CALLCONV *retro_midi_input_enabled_t)(void);
+
+/* Retrieves the current state of the MIDI output.
+ * Returns true if it's enabled, false otherwise */
+typedef bool (RETRO_CALLCONV *retro_midi_output_enabled_t)(void);
+
+/* Reads next byte from the input stream.
+ * Returns true if byte is read, false otherwise. */
+typedef bool (RETRO_CALLCONV *retro_midi_read_t)(uint8_t *byte);
+
+/* Writes byte to the output stream.
+ * 'delta_time' is in microseconds and represent time elapsed since previous write.
+ * Returns true if byte is written, false otherwise. */
+typedef bool (RETRO_CALLCONV *retro_midi_write_t)(uint8_t byte, uint32_t delta_time);
+
+/* Flushes previously written data.
+ * Returns true if successful, false otherwise. */
+typedef bool (RETRO_CALLCONV *retro_midi_flush_t)(void);
+
+struct retro_midi_interface
+{
+ retro_midi_input_enabled_t input_enabled;
+ retro_midi_output_enabled_t output_enabled;
+ retro_midi_read_t read;
+ retro_midi_write_t write;
+ retro_midi_flush_t flush;
+};
+
+enum retro_hw_render_context_negotiation_interface_type
+{
+ RETRO_HW_RENDER_CONTEXT_NEGOTIATION_INTERFACE_VULKAN = 0,
+ RETRO_HW_RENDER_CONTEXT_NEGOTIATION_INTERFACE_DUMMY = INT_MAX
+};
+
+/* Base struct. All retro_hw_render_context_negotiation_interface_* types
+ * contain at least these fields. */
+struct retro_hw_render_context_negotiation_interface
+{
+ enum retro_hw_render_context_negotiation_interface_type interface_type;
+ unsigned interface_version;
+};
+
+/* Serialized state is incomplete in some way. Set if serialization is
+ * usable in typical end-user cases but should not be relied upon to
+ * implement frame-sensitive frontend features such as netplay or
+ * rerecording. */
+#define RETRO_SERIALIZATION_QUIRK_INCOMPLETE (1 << 0)
+/* The core must spend some time initializing before serialization is
+ * supported. retro_serialize() will initially fail; retro_unserialize()
+ * and retro_serialize_size() may or may not work correctly either. */
+#define RETRO_SERIALIZATION_QUIRK_MUST_INITIALIZE (1 << 1)
+/* Serialization size may change within a session. */
+#define RETRO_SERIALIZATION_QUIRK_CORE_VARIABLE_SIZE (1 << 2)
+/* Set by the frontend to acknowledge that it supports variable-sized
+ * states. */
+#define RETRO_SERIALIZATION_QUIRK_FRONT_VARIABLE_SIZE (1 << 3)
+/* Serialized state can only be loaded during the same session. */
+#define RETRO_SERIALIZATION_QUIRK_SINGLE_SESSION (1 << 4)
+/* Serialized state cannot be loaded on an architecture with a different
+ * endianness from the one it was saved on. */
+#define RETRO_SERIALIZATION_QUIRK_ENDIAN_DEPENDENT (1 << 5)
+/* Serialized state cannot be loaded on a different platform from the one it
+ * was saved on for reasons other than endianness, such as word size
+ * dependence */
+#define RETRO_SERIALIZATION_QUIRK_PLATFORM_DEPENDENT (1 << 6)
+
+#define RETRO_MEMDESC_CONST (1 << 0) /* The frontend will never change this memory area once retro_load_game has returned. */
+#define RETRO_MEMDESC_BIGENDIAN (1 << 1) /* The memory area contains big endian data. Default is little endian. */
+#define RETRO_MEMDESC_SYSTEM_RAM (1 << 2) /* The memory area is system RAM. This is main RAM of the gaming system. */
+#define RETRO_MEMDESC_SAVE_RAM (1 << 3) /* The memory area is save RAM. This RAM is usually found on a game cartridge, backed up by a battery. */
+#define RETRO_MEMDESC_VIDEO_RAM (1 << 4) /* The memory area is video RAM (VRAM) */
+#define RETRO_MEMDESC_ALIGN_2 (1 << 16) /* All memory access in this area is aligned to their own size, or 2, whichever is smaller. */
+#define RETRO_MEMDESC_ALIGN_4 (2 << 16)
+#define RETRO_MEMDESC_ALIGN_8 (3 << 16)
+#define RETRO_MEMDESC_MINSIZE_2 (1 << 24) /* All memory in this region is accessed at least 2 bytes at the time. */
+#define RETRO_MEMDESC_MINSIZE_4 (2 << 24)
+#define RETRO_MEMDESC_MINSIZE_8 (3 << 24)
+struct retro_memory_descriptor
+{
+ uint64_t flags;
+
+ /* Pointer to the start of the relevant ROM or RAM chip.
+ * It's strongly recommended to use 'offset' if possible, rather than
+ * doing math on the pointer.
+ *
+ * If the same byte is mapped my multiple descriptors, their descriptors
+ * must have the same pointer.
+ * If 'start' does not point to the first byte in the pointer, put the
+ * difference in 'offset' instead.
+ *
+ * May be NULL if there's nothing usable here (e.g. hardware registers and
+ * open bus). No flags should be set if the pointer is NULL.
+ * It's recommended to minimize the number of descriptors if possible,
+ * but not mandatory. */
+ void *ptr;
+ size_t offset;
+
+ /* This is the location in the emulated address space
+ * where the mapping starts. */
+ size_t start;
+
+ /* Which bits must be same as in 'start' for this mapping to apply.
+ * The first memory descriptor to claim a certain byte is the one
+ * that applies.
+ * A bit which is set in 'start' must also be set in this.
+ * Can be zero, in which case each byte is assumed mapped exactly once.
+ * In this case, 'len' must be a power of two. */
+ size_t select;
+
+ /* If this is nonzero, the set bits are assumed not connected to the
+ * memory chip's address pins. */
+ size_t disconnect;
+
+ /* This one tells the size of the current memory area.
+ * If, after start+disconnect are applied, the address is higher than
+ * this, the highest bit of the address is cleared.
+ *
+ * If the address is still too high, the next highest bit is cleared.
+ * Can be zero, in which case it's assumed to be infinite (as limited
+ * by 'select' and 'disconnect'). */
+ size_t len;
+
+ /* To go from emulated address to physical address, the following
+ * order applies:
+ * Subtract 'start', pick off 'disconnect', apply 'len', add 'offset'. */
+
+ /* The address space name must consist of only a-zA-Z0-9_-,
+ * should be as short as feasible (maximum length is 8 plus the NUL),
+ * and may not be any other address space plus one or more 0-9A-F
+ * at the end.
+ * However, multiple memory descriptors for the same address space is
+ * allowed, and the address space name can be empty. NULL is treated
+ * as empty.
+ *
+ * Address space names are case sensitive, but avoid lowercase if possible.
+ * The same pointer may exist in multiple address spaces.
+ *
+ * Examples:
+ * blank+blank - valid (multiple things may be mapped in the same namespace)
+ * 'Sp'+'Sp' - valid (multiple things may be mapped in the same namespace)
+ * 'A'+'B' - valid (neither is a prefix of each other)
+ * 'S'+blank - valid ('S' is not in 0-9A-F)
+ * 'a'+blank - valid ('a' is not in 0-9A-F)
+ * 'a'+'A' - valid (neither is a prefix of each other)
+ * 'AR'+blank - valid ('R' is not in 0-9A-F)
+ * 'ARB'+blank - valid (the B can't be part of the address either, because
+ * there is no namespace 'AR')
+ * blank+'B' - not valid, because it's ambigous which address space B1234
+ * would refer to.
+ * The length can't be used for that purpose; the frontend may want
+ * to append arbitrary data to an address, without a separator. */
+ const char *addrspace;
+
+ /* TODO: When finalizing this one, add a description field, which should be
+ * "WRAM" or something roughly equally long. */
+
+ /* TODO: When finalizing this one, replace 'select' with 'limit', which tells
+ * which bits can vary and still refer to the same address (limit = ~select).
+ * TODO: limit? range? vary? something else? */
+
+ /* TODO: When finalizing this one, if 'len' is above what 'select' (or
+ * 'limit') allows, it's bankswitched. Bankswitched data must have both 'len'
+ * and 'select' != 0, and the mappings don't tell how the system switches the
+ * banks. */
+
+ /* TODO: When finalizing this one, fix the 'len' bit removal order.
+ * For len=0x1800, pointer 0x1C00 should go to 0x1400, not 0x0C00.
+ * Algorithm: Take bits highest to lowest, but if it goes above len, clear
+ * the most recent addition and continue on the next bit.
+ * TODO: Can the above be optimized? Is "remove the lowest bit set in both
+ * pointer and 'len'" equivalent? */
+
+ /* TODO: Some emulators (MAME?) emulate big endian systems by only accessing
+ * the emulated memory in 32-bit chunks, native endian. But that's nothing
+ * compared to Darek Mihocka <http://www.emulators.com/docs/nx07_vm101.htm>
+ * (section Emulation 103 - Nearly Free Byte Reversal) - he flips the ENTIRE
+ * RAM backwards! I'll want to represent both of those, via some flags.
+ *
+ * I suspect MAME either didn't think of that idea, or don't want the #ifdef.
+ * Not sure which, nor do I really care. */
+
+ /* TODO: Some of those flags are unused and/or don't really make sense. Clean
+ * them up. */
+};
+
+/* The frontend may use the largest value of 'start'+'select' in a
+ * certain namespace to infer the size of the address space.
+ *
+ * If the address space is larger than that, a mapping with .ptr=NULL
+ * should be at the end of the array, with .select set to all ones for
+ * as long as the address space is big.
+ *
+ * Sample descriptors (minus .ptr, and RETRO_MEMFLAG_ on the flags):
+ * SNES WRAM:
+ * .start=0x7E0000, .len=0x20000
+ * (Note that this must be mapped before the ROM in most cases; some of the
+ * ROM mappers
+ * try to claim $7E0000, or at least $7E8000.)
+ * SNES SPC700 RAM:
+ * .addrspace="S", .len=0x10000
+ * SNES WRAM mirrors:
+ * .flags=MIRROR, .start=0x000000, .select=0xC0E000, .len=0x2000
+ * .flags=MIRROR, .start=0x800000, .select=0xC0E000, .len=0x2000
+ * SNES WRAM mirrors, alternate equivalent descriptor:
+ * .flags=MIRROR, .select=0x40E000, .disconnect=~0x1FFF
+ * (Various similar constructions can be created by combining parts of
+ * the above two.)
+ * SNES LoROM (512KB, mirrored a couple of times):
+ * .flags=CONST, .start=0x008000, .select=0x408000, .disconnect=0x8000, .len=512*1024
+ * .flags=CONST, .start=0x400000, .select=0x400000, .disconnect=0x8000, .len=512*1024
+ * SNES HiROM (4MB):
+ * .flags=CONST, .start=0x400000, .select=0x400000, .len=4*1024*1024
+ * .flags=CONST, .offset=0x8000, .start=0x008000, .select=0x408000, .len=4*1024*1024
+ * SNES ExHiROM (8MB):
+ * .flags=CONST, .offset=0, .start=0xC00000, .select=0xC00000, .len=4*1024*1024
+ * .flags=CONST, .offset=4*1024*1024, .start=0x400000, .select=0xC00000, .len=4*1024*1024
+ * .flags=CONST, .offset=0x8000, .start=0x808000, .select=0xC08000, .len=4*1024*1024
+ * .flags=CONST, .offset=4*1024*1024+0x8000, .start=0x008000, .select=0xC08000, .len=4*1024*1024
+ * Clarify the size of the address space:
+ * .ptr=NULL, .select=0xFFFFFF
+ * .len can be implied by .select in many of them, but was included for clarity.
+ */
+
+struct retro_memory_map
+{
+ const struct retro_memory_descriptor *descriptors;
+ unsigned num_descriptors;
+};
+
+struct retro_controller_description
+{
+ /* Human-readable description of the controller. Even if using a generic
+ * input device type, this can be set to the particular device type the
+ * core uses. */
+ const char *desc;
+
+ /* Device type passed to retro_set_controller_port_device(). If the device
+ * type is a sub-class of a generic input device type, use the
+ * RETRO_DEVICE_SUBCLASS macro to create an ID.
+ *
+ * E.g. RETRO_DEVICE_SUBCLASS(RETRO_DEVICE_JOYPAD, 1). */
+ unsigned id;
+};
+
+struct retro_controller_info
+{
+ const struct retro_controller_description *types;
+ unsigned num_types;
+};
+
+struct retro_subsystem_memory_info
+{
+ /* The extension associated with a memory type, e.g. "psram". */
+ const char *extension;
+
+ /* The memory type for retro_get_memory(). This should be at
+ * least 0x100 to avoid conflict with standardized
+ * libretro memory types. */
+ unsigned type;
+};
+
+struct retro_subsystem_rom_info
+{
+ /* Describes what the content is (SGB BIOS, GB ROM, etc). */
+ const char *desc;
+
+ /* Same definition as retro_get_system_info(). */
+ const char *valid_extensions;
+
+ /* Same definition as retro_get_system_info(). */
+ bool need_fullpath;
+
+ /* Same definition as retro_get_system_info(). */
+ bool block_extract;
+
+ /* This is set if the content is required to load a game.
+ * If this is set to false, a zeroed-out retro_game_info can be passed. */
+ bool required;
+
+ /* Content can have multiple associated persistent
+ * memory types (retro_get_memory()). */
+ const struct retro_subsystem_memory_info *memory;
+ unsigned num_memory;
+};
+
+struct retro_subsystem_info
+{
+ /* Human-readable string of the subsystem type, e.g. "Super GameBoy" */
+ const char *desc;
+
+ /* A computer friendly short string identifier for the subsystem type.
+ * This name must be [a-z].
+ * E.g. if desc is "Super GameBoy", this can be "sgb".
+ * This identifier can be used for command-line interfaces, etc.
+ */
+ const char *ident;
+
+ /* Infos for each content file. The first entry is assumed to be the
+ * "most significant" content for frontend purposes.
+ * E.g. with Super GameBoy, the first content should be the GameBoy ROM,
+ * as it is the most "significant" content to a user.
+ * If a frontend creates new file paths based on the content used
+ * (e.g. savestates), it should use the path for the first ROM to do so. */
+ const struct retro_subsystem_rom_info *roms;
+
+ /* Number of content files associated with a subsystem. */
+ unsigned num_roms;
+
+ /* The type passed to retro_load_game_special(). */
+ unsigned id;
+};
+
+typedef void (RETRO_CALLCONV *retro_proc_address_t)(void);
+
+/* libretro API extension functions:
+ * (None here so far).
+ *
+ * Get a symbol from a libretro core.
+ * Cores should only return symbols which are actual
+ * extensions to the libretro API.
+ *
+ * Frontends should not use this to obtain symbols to standard
+ * libretro entry points (static linking or dlsym).
+ *
+ * The symbol name must be equal to the function name,
+ * e.g. if void retro_foo(void); exists, the symbol must be called "retro_foo".
+ * The returned function pointer must be cast to the corresponding type.
+ */
+typedef retro_proc_address_t (RETRO_CALLCONV *retro_get_proc_address_t)(const char *sym);
+
+struct retro_get_proc_address_interface
+{
+ retro_get_proc_address_t get_proc_address;
+};
+
+enum retro_log_level
+{
+ RETRO_LOG_DEBUG = 0,
+ RETRO_LOG_INFO,
+ RETRO_LOG_WARN,
+ RETRO_LOG_ERROR,
+
+ RETRO_LOG_DUMMY = INT_MAX
+};
+
+/* Logging function. Takes log level argument as well. */
+typedef void (RETRO_CALLCONV *retro_log_printf_t)(enum retro_log_level level,
+ const char *fmt, ...);
+
+struct retro_log_callback
+{
+ retro_log_printf_t log;
+};
+
+/* Performance related functions */
+
+/* ID values for SIMD CPU features */
+#define RETRO_SIMD_SSE (1 << 0)
+#define RETRO_SIMD_SSE2 (1 << 1)
+#define RETRO_SIMD_VMX (1 << 2)
+#define RETRO_SIMD_VMX128 (1 << 3)
+#define RETRO_SIMD_AVX (1 << 4)
+#define RETRO_SIMD_NEON (1 << 5)
+#define RETRO_SIMD_SSE3 (1 << 6)
+#define RETRO_SIMD_SSSE3 (1 << 7)
+#define RETRO_SIMD_MMX (1 << 8)
+#define RETRO_SIMD_MMXEXT (1 << 9)
+#define RETRO_SIMD_SSE4 (1 << 10)
+#define RETRO_SIMD_SSE42 (1 << 11)
+#define RETRO_SIMD_AVX2 (1 << 12)
+#define RETRO_SIMD_VFPU (1 << 13)
+#define RETRO_SIMD_PS (1 << 14)
+#define RETRO_SIMD_AES (1 << 15)
+#define RETRO_SIMD_VFPV3 (1 << 16)
+#define RETRO_SIMD_VFPV4 (1 << 17)
+#define RETRO_SIMD_POPCNT (1 << 18)
+#define RETRO_SIMD_MOVBE (1 << 19)
+#define RETRO_SIMD_CMOV (1 << 20)
+#define RETRO_SIMD_ASIMD (1 << 21)
+
+typedef uint64_t retro_perf_tick_t;
+typedef int64_t retro_time_t;
+
+struct retro_perf_counter
+{
+ const char *ident;
+ retro_perf_tick_t start;
+ retro_perf_tick_t total;
+ retro_perf_tick_t call_cnt;
+
+ bool registered;
+};
+
+/* Returns current time in microseconds.
+ * Tries to use the most accurate timer available.
+ */
+typedef retro_time_t (RETRO_CALLCONV *retro_perf_get_time_usec_t)(void);
+
+/* A simple counter. Usually nanoseconds, but can also be CPU cycles.
+ * Can be used directly if desired (when creating a more sophisticated
+ * performance counter system).
+ * */
+typedef retro_perf_tick_t (RETRO_CALLCONV *retro_perf_get_counter_t)(void);
+
+/* Returns a bit-mask of detected CPU features (RETRO_SIMD_*). */
+typedef uint64_t (RETRO_CALLCONV *retro_get_cpu_features_t)(void);
+
+/* Asks frontend to log and/or display the state of performance counters.
+ * Performance counters can always be poked into manually as well.
+ */
+typedef void (RETRO_CALLCONV *retro_perf_log_t)(void);
+
+/* Register a performance counter.
+ * ident field must be set with a discrete value and other values in
+ * retro_perf_counter must be 0.
+ * Registering can be called multiple times. To avoid calling to
+ * frontend redundantly, you can check registered field first. */
+typedef void (RETRO_CALLCONV *retro_perf_register_t)(struct retro_perf_counter *counter);
+
+/* Starts a registered counter. */
+typedef void (RETRO_CALLCONV *retro_perf_start_t)(struct retro_perf_counter *counter);
+
+/* Stops a registered counter. */
+typedef void (RETRO_CALLCONV *retro_perf_stop_t)(struct retro_perf_counter *counter);
+
+/* For convenience it can be useful to wrap register, start and stop in macros.
+ * E.g.:
+ * #ifdef LOG_PERFORMANCE
+ * #define RETRO_PERFORMANCE_INIT(perf_cb, name) static struct retro_perf_counter name = {#name}; if (!name.registered) perf_cb.perf_register(&(name))
+ * #define RETRO_PERFORMANCE_START(perf_cb, name) perf_cb.perf_start(&(name))
+ * #define RETRO_PERFORMANCE_STOP(perf_cb, name) perf_cb.perf_stop(&(name))
+ * #else
+ * ... Blank macros ...
+ * #endif
+ *
+ * These can then be used mid-functions around code snippets.
+ *
+ * extern struct retro_perf_callback perf_cb; * Somewhere in the core.
+ *
+ * void do_some_heavy_work(void)
+ * {
+ * RETRO_PERFORMANCE_INIT(cb, work_1;
+ * RETRO_PERFORMANCE_START(cb, work_1);
+ * heavy_work_1();
+ * RETRO_PERFORMANCE_STOP(cb, work_1);
+ *
+ * RETRO_PERFORMANCE_INIT(cb, work_2);
+ * RETRO_PERFORMANCE_START(cb, work_2);
+ * heavy_work_2();
+ * RETRO_PERFORMANCE_STOP(cb, work_2);
+ * }
+ *
+ * void retro_deinit(void)
+ * {
+ * perf_cb.perf_log(); * Log all perf counters here for example.
+ * }
+ */
+
+struct retro_perf_callback
+{
+ retro_perf_get_time_usec_t get_time_usec;
+ retro_get_cpu_features_t get_cpu_features;
+
+ retro_perf_get_counter_t get_perf_counter;
+ retro_perf_register_t perf_register;
+ retro_perf_start_t perf_start;
+ retro_perf_stop_t perf_stop;
+ retro_perf_log_t perf_log;
+};
+
+/* FIXME: Document the sensor API and work out behavior.
+ * It will be marked as experimental until then.
+ */
+enum retro_sensor_action
+{
+ RETRO_SENSOR_ACCELEROMETER_ENABLE = 0,
+ RETRO_SENSOR_ACCELEROMETER_DISABLE,
+ RETRO_SENSOR_GYROSCOPE_ENABLE,
+ RETRO_SENSOR_GYROSCOPE_DISABLE,
+ RETRO_SENSOR_ILLUMINANCE_ENABLE,
+ RETRO_SENSOR_ILLUMINANCE_DISABLE,
+
+ RETRO_SENSOR_DUMMY = INT_MAX
+};
+
+/* Id values for SENSOR types. */
+#define RETRO_SENSOR_ACCELEROMETER_X 0
+#define RETRO_SENSOR_ACCELEROMETER_Y 1
+#define RETRO_SENSOR_ACCELEROMETER_Z 2
+#define RETRO_SENSOR_GYROSCOPE_X 3
+#define RETRO_SENSOR_GYROSCOPE_Y 4
+#define RETRO_SENSOR_GYROSCOPE_Z 5
+#define RETRO_SENSOR_ILLUMINANCE 6
+
+typedef bool (RETRO_CALLCONV *retro_set_sensor_state_t)(unsigned port,
+ enum retro_sensor_action action, unsigned rate);
+
+typedef float (RETRO_CALLCONV *retro_sensor_get_input_t)(unsigned port, unsigned id);
+
+struct retro_sensor_interface
+{
+ retro_set_sensor_state_t set_sensor_state;
+ retro_sensor_get_input_t get_sensor_input;
+};
+
+enum retro_camera_buffer
+{
+ RETRO_CAMERA_BUFFER_OPENGL_TEXTURE = 0,
+ RETRO_CAMERA_BUFFER_RAW_FRAMEBUFFER,
+
+ RETRO_CAMERA_BUFFER_DUMMY = INT_MAX
+};
+
+/* Starts the camera driver. Can only be called in retro_run(). */
+typedef bool (RETRO_CALLCONV *retro_camera_start_t)(void);
+
+/* Stops the camera driver. Can only be called in retro_run(). */
+typedef void (RETRO_CALLCONV *retro_camera_stop_t)(void);
+
+/* Callback which signals when the camera driver is initialized
+ * and/or deinitialized.
+ * retro_camera_start_t can be called in initialized callback.
+ */
+typedef void (RETRO_CALLCONV *retro_camera_lifetime_status_t)(void);
+
+/* A callback for raw framebuffer data. buffer points to an XRGB8888 buffer.
+ * Width, height and pitch are similar to retro_video_refresh_t.
+ * First pixel is top-left origin.
+ */
+typedef void (RETRO_CALLCONV *retro_camera_frame_raw_framebuffer_t)(const uint32_t *buffer,
+ unsigned width, unsigned height, size_t pitch);
+
+/* A callback for when OpenGL textures are used.
+ *
+ * texture_id is a texture owned by camera driver.
+ * Its state or content should be considered immutable, except for things like
+ * texture filtering and clamping.
+ *
+ * texture_target is the texture target for the GL texture.
+ * These can include e.g. GL_TEXTURE_2D, GL_TEXTURE_RECTANGLE, and possibly
+ * more depending on extensions.
+ *
+ * affine points to a packed 3x3 column-major matrix used to apply an affine
+ * transform to texture coordinates. (affine_matrix * vec3(coord_x, coord_y, 1.0))
+ * After transform, normalized texture coord (0, 0) should be bottom-left
+ * and (1, 1) should be top-right (or (width, height) for RECTANGLE).
+ *
+ * GL-specific typedefs are avoided here to avoid relying on gl.h in
+ * the API definition.
+ */
+typedef void (RETRO_CALLCONV *retro_camera_frame_opengl_texture_t)(unsigned texture_id,
+ unsigned texture_target, const float *affine);
+
+struct retro_camera_callback
+{
+ /* Set by libretro core.
+ * Example bitmask: caps = (1 << RETRO_CAMERA_BUFFER_OPENGL_TEXTURE) | (1 << RETRO_CAMERA_BUFFER_RAW_FRAMEBUFFER).
+ */
+ uint64_t caps;
+
+ /* Desired resolution for camera. Is only used as a hint. */
+ unsigned width;
+ unsigned height;
+
+ /* Set by frontend. */
+ retro_camera_start_t start;
+ retro_camera_stop_t stop;
+
+ /* Set by libretro core if raw framebuffer callbacks will be used. */
+ retro_camera_frame_raw_framebuffer_t frame_raw_framebuffer;
+
+ /* Set by libretro core if OpenGL texture callbacks will be used. */
+ retro_camera_frame_opengl_texture_t frame_opengl_texture;
+
+ /* Set by libretro core. Called after camera driver is initialized and
+ * ready to be started.
+ * Can be NULL, in which this callback is not called.
+ */
+ retro_camera_lifetime_status_t initialized;
+
+ /* Set by libretro core. Called right before camera driver is
+ * deinitialized.
+ * Can be NULL, in which this callback is not called.
+ */
+ retro_camera_lifetime_status_t deinitialized;
+};
+
+/* Sets the interval of time and/or distance at which to update/poll
+ * location-based data.
+ *
+ * To ensure compatibility with all location-based implementations,
+ * values for both interval_ms and interval_distance should be provided.
+ *
+ * interval_ms is the interval expressed in milliseconds.
+ * interval_distance is the distance interval expressed in meters.
+ */
+typedef void (RETRO_CALLCONV *retro_location_set_interval_t)(unsigned interval_ms,
+ unsigned interval_distance);
+
+/* Start location services. The device will start listening for changes to the
+ * current location at regular intervals (which are defined with
+ * retro_location_set_interval_t). */
+typedef bool (RETRO_CALLCONV *retro_location_start_t)(void);
+
+/* Stop location services. The device will stop listening for changes
+ * to the current location. */
+typedef void (RETRO_CALLCONV *retro_location_stop_t)(void);
+
+/* Get the position of the current location. Will set parameters to
+ * 0 if no new location update has happened since the last time. */
+typedef bool (RETRO_CALLCONV *retro_location_get_position_t)(double *lat, double *lon,
+ double *horiz_accuracy, double *vert_accuracy);
+
+/* Callback which signals when the location driver is initialized
+ * and/or deinitialized.
+ * retro_location_start_t can be called in initialized callback.
+ */
+typedef void (RETRO_CALLCONV *retro_location_lifetime_status_t)(void);
+
+struct retro_location_callback
+{
+ retro_location_start_t start;
+ retro_location_stop_t stop;
+ retro_location_get_position_t get_position;
+ retro_location_set_interval_t set_interval;
+
+ retro_location_lifetime_status_t initialized;
+ retro_location_lifetime_status_t deinitialized;
+};
+
+enum retro_rumble_effect
+{
+ RETRO_RUMBLE_STRONG = 0,
+ RETRO_RUMBLE_WEAK = 1,
+
+ RETRO_RUMBLE_DUMMY = INT_MAX
+};
+
+/* Sets rumble state for joypad plugged in port 'port'.
+ * Rumble effects are controlled independently,
+ * and setting e.g. strong rumble does not override weak rumble.
+ * Strength has a range of [0, 0xffff].
+ *
+ * Returns true if rumble state request was honored.
+ * Calling this before first retro_run() is likely to return false. */
+typedef bool (RETRO_CALLCONV *retro_set_rumble_state_t)(unsigned port,
+ enum retro_rumble_effect effect, uint16_t strength);
+
+struct retro_rumble_interface
+{
+ retro_set_rumble_state_t set_rumble_state;
+};
+
+/* Notifies libretro that audio data should be written. */
+typedef void (RETRO_CALLCONV *retro_audio_callback_t)(void);
+
+/* True: Audio driver in frontend is active, and callback is
+ * expected to be called regularily.
+ * False: Audio driver in frontend is paused or inactive.
+ * Audio callback will not be called until set_state has been
+ * called with true.
+ * Initial state is false (inactive).
+ */
+typedef void (RETRO_CALLCONV *retro_audio_set_state_callback_t)(bool enabled);
+
+struct retro_audio_callback
+{
+ retro_audio_callback_t callback;
+ retro_audio_set_state_callback_t set_state;
+};
+
+/* Notifies a libretro core of time spent since last invocation
+ * of retro_run() in microseconds.
+ *
+ * It will be called right before retro_run() every frame.
+ * The frontend can tamper with timing to support cases like
+ * fast-forward, slow-motion and framestepping.
+ *
+ * In those scenarios the reference frame time value will be used. */
+typedef int64_t retro_usec_t;
+typedef void (RETRO_CALLCONV *retro_frame_time_callback_t)(retro_usec_t usec);
+struct retro_frame_time_callback
+{
+ retro_frame_time_callback_t callback;
+ /* Represents the time of one frame. It is computed as
+ * 1000000 / fps, but the implementation will resolve the
+ * rounding to ensure that framestepping, etc is exact. */
+ retro_usec_t reference;
+};
+
+/* Notifies a libretro core of the current occupancy
+ * level of the frontend audio buffer.
+ *
+ * - active: 'true' if audio buffer is currently
+ * in use. Will be 'false' if audio is
+ * disabled in the frontend
+ *
+ * - occupancy: Given as a value in the range [0,100],
+ * corresponding to the occupancy percentage
+ * of the audio buffer
+ *
+ * - underrun_likely: 'true' if the frontend expects an
+ * audio buffer underrun during the
+ * next frame (indicates that a core
+ * should attempt frame skipping)
+ *
+ * It will be called right before retro_run() every frame. */
+typedef void (RETRO_CALLCONV *retro_audio_buffer_status_callback_t)(
+ bool active, unsigned occupancy, bool underrun_likely);
+struct retro_audio_buffer_status_callback
+{
+ retro_audio_buffer_status_callback_t callback;
+};
+
+/* Pass this to retro_video_refresh_t if rendering to hardware.
+ * Passing NULL to retro_video_refresh_t is still a frame dupe as normal.
+ * */
+#define RETRO_HW_FRAME_BUFFER_VALID ((void*)-1)
+
+/* Invalidates the current HW context.
+ * Any GL state is lost, and must not be deinitialized explicitly.
+ * If explicit deinitialization is desired by the libretro core,
+ * it should implement context_destroy callback.
+ * If called, all GPU resources must be reinitialized.
+ * Usually called when frontend reinits video driver.
+ * Also called first time video driver is initialized,
+ * allowing libretro core to initialize resources.
+ */
+typedef void (RETRO_CALLCONV *retro_hw_context_reset_t)(void);
+
+/* Gets current framebuffer which is to be rendered to.
+ * Could change every frame potentially.
+ */
+typedef uintptr_t (RETRO_CALLCONV *retro_hw_get_current_framebuffer_t)(void);
+
+/* Get a symbol from HW context. */
+typedef retro_proc_address_t (RETRO_CALLCONV *retro_hw_get_proc_address_t)(const char *sym);
+
+enum retro_hw_context_type
+{
+ RETRO_HW_CONTEXT_NONE = 0,
+ /* OpenGL 2.x. Driver can choose to use latest compatibility context. */
+ RETRO_HW_CONTEXT_OPENGL = 1,
+ /* OpenGL ES 2.0. */
+ RETRO_HW_CONTEXT_OPENGLES2 = 2,
+ /* Modern desktop core GL context. Use version_major/
+ * version_minor fields to set GL version. */
+ RETRO_HW_CONTEXT_OPENGL_CORE = 3,
+ /* OpenGL ES 3.0 */
+ RETRO_HW_CONTEXT_OPENGLES3 = 4,
+ /* OpenGL ES 3.1+. Set version_major/version_minor. For GLES2 and GLES3,
+ * use the corresponding enums directly. */
+ RETRO_HW_CONTEXT_OPENGLES_VERSION = 5,
+
+ /* Vulkan, see RETRO_ENVIRONMENT_GET_HW_RENDER_INTERFACE. */
+ RETRO_HW_CONTEXT_VULKAN = 6,
+
+ /* Direct3D, set version_major to select the type of interface
+ * returned by RETRO_ENVIRONMENT_GET_HW_RENDER_INTERFACE */
+ RETRO_HW_CONTEXT_DIRECT3D = 7,
+
+ RETRO_HW_CONTEXT_DUMMY = INT_MAX
+};
+
+struct retro_hw_render_callback
+{
+ /* Which API to use. Set by libretro core. */
+ enum retro_hw_context_type context_type;
+
+ /* Called when a context has been created or when it has been reset.
+ * An OpenGL context is only valid after context_reset() has been called.
+ *
+ * When context_reset is called, OpenGL resources in the libretro
+ * implementation are guaranteed to be invalid.
+ *
+ * It is possible that context_reset is called multiple times during an
+ * application lifecycle.
+ * If context_reset is called without any notification (context_destroy),
+ * the OpenGL context was lost and resources should just be recreated
+ * without any attempt to "free" old resources.
+ */
+ retro_hw_context_reset_t context_reset;
+
+ /* Set by frontend.
+ * TODO: This is rather obsolete. The frontend should not
+ * be providing preallocated framebuffers. */
+ retro_hw_get_current_framebuffer_t get_current_framebuffer;
+
+ /* Set by frontend.
+ * Can return all relevant functions, including glClear on Windows. */
+ retro_hw_get_proc_address_t get_proc_address;
+
+ /* Set if render buffers should have depth component attached.
+ * TODO: Obsolete. */
+ bool depth;
+
+ /* Set if stencil buffers should be attached.
+ * TODO: Obsolete. */
+ bool stencil;
+
+ /* If depth and stencil are true, a packed 24/8 buffer will be added.
+ * Only attaching stencil is invalid and will be ignored. */
+
+ /* Use conventional bottom-left origin convention. If false,
+ * standard libretro top-left origin semantics are used.
+ * TODO: Move to GL specific interface. */
+ bool bottom_left_origin;
+
+ /* Major version number for core GL context or GLES 3.1+. */
+ unsigned version_major;
+
+ /* Minor version number for core GL context or GLES 3.1+. */
+ unsigned version_minor;
+
+ /* If this is true, the frontend will go very far to avoid
+ * resetting context in scenarios like toggling fullscreen, etc.
+ * TODO: Obsolete? Maybe frontend should just always assume this ...
+ */
+ bool cache_context;
+
+ /* The reset callback might still be called in extreme situations
+ * such as if the context is lost beyond recovery.
+ *
+ * For optimal stability, set this to false, and allow context to be
+ * reset at any time.
+ */
+
+ /* A callback to be called before the context is destroyed in a
+ * controlled way by the frontend. */
+ retro_hw_context_reset_t context_destroy;
+
+ /* OpenGL resources can be deinitialized cleanly at this step.
+ * context_destroy can be set to NULL, in which resources will
+ * just be destroyed without any notification.
+ *
+ * Even when context_destroy is non-NULL, it is possible that
+ * context_reset is called without any destroy notification.
+ * This happens if context is lost by external factors (such as
+ * notified by GL_ARB_robustness).
+ *
+ * In this case, the context is assumed to be already dead,
+ * and the libretro implementation must not try to free any OpenGL
+ * resources in the subsequent context_reset.
+ */
+
+ /* Creates a debug context. */
+ bool debug_context;
+};
+
+/* Callback type passed in RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK.
+ * Called by the frontend in response to keyboard events.
+ * down is set if the key is being pressed, or false if it is being released.
+ * keycode is the RETROK value of the char.
+ * character is the text character of the pressed key. (UTF-32).
+ * key_modifiers is a set of RETROKMOD values or'ed together.
+ *
+ * The pressed/keycode state can be indepedent of the character.
+ * It is also possible that multiple characters are generated from a
+ * single keypress.
+ * Keycode events should be treated separately from character events.
+ * However, when possible, the frontend should try to synchronize these.
+ * If only a character is posted, keycode should be RETROK_UNKNOWN.
+ *
+ * Similarily if only a keycode event is generated with no corresponding
+ * character, character should be 0.
+ */
+typedef void (RETRO_CALLCONV *retro_keyboard_event_t)(bool down, unsigned keycode,
+ uint32_t character, uint16_t key_modifiers);
+
+struct retro_keyboard_callback
+{
+ retro_keyboard_event_t callback;
+};
+
+/* Callbacks for RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE &
+ * RETRO_ENVIRONMENT_SET_DISK_CONTROL_EXT_INTERFACE.
+ * Should be set for implementations which can swap out multiple disk
+ * images in runtime.
+ *
+ * If the implementation can do this automatically, it should strive to do so.
+ * However, there are cases where the user must manually do so.
+ *
+ * Overview: To swap a disk image, eject the disk image with
+ * set_eject_state(true).
+ * Set the disk index with set_image_index(index). Insert the disk again
+ * with set_eject_state(false).
+ */
+
+/* If ejected is true, "ejects" the virtual disk tray.
+ * When ejected, the disk image index can be set.
+ */
+typedef bool (RETRO_CALLCONV *retro_set_eject_state_t)(bool ejected);
+
+/* Gets current eject state. The initial state is 'not ejected'. */
+typedef bool (RETRO_CALLCONV *retro_get_eject_state_t)(void);
+
+/* Gets current disk index. First disk is index 0.
+ * If return value is >= get_num_images(), no disk is currently inserted.
+ */
+typedef unsigned (RETRO_CALLCONV *retro_get_image_index_t)(void);
+
+/* Sets image index. Can only be called when disk is ejected.
+ * The implementation supports setting "no disk" by using an
+ * index >= get_num_images().
+ */
+typedef bool (RETRO_CALLCONV *retro_set_image_index_t)(unsigned index);
+
+/* Gets total number of images which are available to use. */
+typedef unsigned (RETRO_CALLCONV *retro_get_num_images_t)(void);
+
+struct retro_game_info;
+
+/* Replaces the disk image associated with index.
+ * Arguments to pass in info have same requirements as retro_load_game().
+ * Virtual disk tray must be ejected when calling this.
+ *
+ * Replacing a disk image with info = NULL will remove the disk image
+ * from the internal list.
+ * As a result, calls to get_image_index() can change.
+ *
+ * E.g. replace_image_index(1, NULL), and previous get_image_index()
+ * returned 4 before.
+ * Index 1 will be removed, and the new index is 3.
+ */
+typedef bool (RETRO_CALLCONV *retro_replace_image_index_t)(unsigned index,
+ const struct retro_game_info *info);
+
+/* Adds a new valid index (get_num_images()) to the internal disk list.
+ * This will increment subsequent return values from get_num_images() by 1.
+ * This image index cannot be used until a disk image has been set
+ * with replace_image_index. */
+typedef bool (RETRO_CALLCONV *retro_add_image_index_t)(void);
+
+/* Sets initial image to insert in drive when calling
+ * core_load_game().
+ * Since we cannot pass the initial index when loading
+ * content (this would require a major API change), this
+ * is set by the frontend *before* calling the core's
+ * retro_load_game()/retro_load_game_special() implementation.
+ * A core should therefore cache the index/path values and handle
+ * them inside retro_load_game()/retro_load_game_special().
+ * - If 'index' is invalid (index >= get_num_images()), the
+ * core should ignore the set value and instead use 0
+ * - 'path' is used purely for error checking - i.e. when
+ * content is loaded, the core should verify that the
+ * disk specified by 'index' has the specified file path.
+ * This is to guard against auto selecting the wrong image
+ * if (for example) the user should modify an existing M3U
+ * playlist. We have to let the core handle this because
+ * set_initial_image() must be called before loading content,
+ * i.e. the frontend cannot access image paths in advance
+ * and thus cannot perform the error check itself.
+ * If set path and content path do not match, the core should
+ * ignore the set 'index' value and instead use 0
+ * Returns 'false' if index or 'path' are invalid, or core
+ * does not support this functionality
+ */
+typedef bool (RETRO_CALLCONV *retro_set_initial_image_t)(unsigned index, const char *path);
+
+/* Fetches the path of the specified disk image file.
+ * Returns 'false' if index is invalid (index >= get_num_images())
+ * or path is otherwise unavailable.
+ */
+typedef bool (RETRO_CALLCONV *retro_get_image_path_t)(unsigned index, char *path, size_t len);
+
+/* Fetches a core-provided 'label' for the specified disk
+ * image file. In the simplest case this may be a file name
+ * (without extension), but for cores with more complex
+ * content requirements information may be provided to
+ * facilitate user disk swapping - for example, a core
+ * running floppy-disk-based content may uniquely label
+ * save disks, data disks, level disks, etc. with names
+ * corresponding to in-game disk change prompts (so the
+ * frontend can provide better user guidance than a 'dumb'
+ * disk index value).
+ * Returns 'false' if index is invalid (index >= get_num_images())
+ * or label is otherwise unavailable.
+ */
+typedef bool (RETRO_CALLCONV *retro_get_image_label_t)(unsigned index, char *label, size_t len);
+
+struct retro_disk_control_callback
+{
+ retro_set_eject_state_t set_eject_state;
+ retro_get_eject_state_t get_eject_state;
+
+ retro_get_image_index_t get_image_index;
+ retro_set_image_index_t set_image_index;
+ retro_get_num_images_t get_num_images;
+
+ retro_replace_image_index_t replace_image_index;
+ retro_add_image_index_t add_image_index;
+};
+
+struct retro_disk_control_ext_callback
+{
+ retro_set_eject_state_t set_eject_state;
+ retro_get_eject_state_t get_eject_state;
+
+ retro_get_image_index_t get_image_index;
+ retro_set_image_index_t set_image_index;
+ retro_get_num_images_t get_num_images;
+
+ retro_replace_image_index_t replace_image_index;
+ retro_add_image_index_t add_image_index;
+
+ /* NOTE: Frontend will only attempt to record/restore
+ * last used disk index if both set_initial_image()
+ * and get_image_path() are implemented */
+ retro_set_initial_image_t set_initial_image; /* Optional - may be NULL */
+
+ retro_get_image_path_t get_image_path; /* Optional - may be NULL */
+ retro_get_image_label_t get_image_label; /* Optional - may be NULL */
+};
+
+enum retro_pixel_format
+{
+ /* 0RGB1555, native endian.
+ * 0 bit must be set to 0.
+ * This pixel format is default for compatibility concerns only.
+ * If a 15/16-bit pixel format is desired, consider using RGB565. */
+ RETRO_PIXEL_FORMAT_0RGB1555 = 0,
+
+ /* XRGB8888, native endian.
+ * X bits are ignored. */
+ RETRO_PIXEL_FORMAT_XRGB8888 = 1,
+
+ /* RGB565, native endian.
+ * This pixel format is the recommended format to use if a 15/16-bit
+ * format is desired as it is the pixel format that is typically
+ * available on a wide range of low-power devices.
+ *
+ * It is also natively supported in APIs like OpenGL ES. */
+ RETRO_PIXEL_FORMAT_RGB565 = 2,
+
+ /* Ensure sizeof() == sizeof(int). */
+ RETRO_PIXEL_FORMAT_UNKNOWN = INT_MAX
+};
+
+struct retro_message
+{
+ const char *msg; /* Message to be displayed. */
+ unsigned frames; /* Duration in frames of message. */
+};
+
+enum retro_message_target
+{
+ RETRO_MESSAGE_TARGET_ALL = 0,
+ RETRO_MESSAGE_TARGET_OSD,
+ RETRO_MESSAGE_TARGET_LOG
+};
+
+enum retro_message_type
+{
+ RETRO_MESSAGE_TYPE_NOTIFICATION = 0,
+ RETRO_MESSAGE_TYPE_NOTIFICATION_ALT,
+ RETRO_MESSAGE_TYPE_STATUS,
+ RETRO_MESSAGE_TYPE_PROGRESS
+};
+
+struct retro_message_ext
+{
+ /* Message string to be displayed/logged */
+ const char *msg;
+ /* Duration (in ms) of message when targeting the OSD */
+ unsigned duration;
+ /* Message priority when targeting the OSD
+ * > When multiple concurrent messages are sent to
+ * the frontend and the frontend does not have the
+ * capacity to display them all, messages with the
+ * *highest* priority value should be shown
+ * > There is no upper limit to a message priority
+ * value (within the bounds of the unsigned data type)
+ * > In the reference frontend (RetroArch), the same
+ * priority values are used for frontend-generated
+ * notifications, which are typically assigned values
+ * between 0 and 3 depending upon importance */
+ unsigned priority;
+ /* Message logging level (info, warn, error, etc.) */
+ enum retro_log_level level;
+ /* Message destination: OSD, logging interface or both */
+ enum retro_message_target target;
+ /* Message 'type' when targeting the OSD
+ * > RETRO_MESSAGE_TYPE_NOTIFICATION: Specifies that a
+ * message should be handled in identical fashion to
+ * a standard frontend-generated notification
+ * > RETRO_MESSAGE_TYPE_NOTIFICATION_ALT: Specifies that
+ * message is a notification that requires user attention
+ * or action, but that it should be displayed in a manner
+ * that differs from standard frontend-generated notifications.
+ * This would typically correspond to messages that should be
+ * displayed immediately (independently from any internal
+ * frontend message queue), and/or which should be visually
+ * distinguishable from frontend-generated notifications.
+ * For example, a core may wish to inform the user of
+ * information related to a disk-change event. It is
+ * expected that the frontend itself may provide a
+ * notification in this case; if the core sends a
+ * message of type RETRO_MESSAGE_TYPE_NOTIFICATION, an
+ * uncomfortable 'double-notification' may occur. A message
+ * of RETRO_MESSAGE_TYPE_NOTIFICATION_ALT should therefore
+ * be presented such that visual conflict with regular
+ * notifications does not occur
+ * > RETRO_MESSAGE_TYPE_STATUS: Indicates that message
+ * is not a standard notification. This typically
+ * corresponds to 'status' indicators, such as a core's
+ * internal FPS, which are intended to be displayed
+ * either permanently while a core is running, or in
+ * a manner that does not suggest user attention or action
+ * is required. 'Status' type messages should therefore be
+ * displayed in a different on-screen location and in a manner
+ * easily distinguishable from both standard frontend-generated
+ * notifications and messages of type RETRO_MESSAGE_TYPE_NOTIFICATION_ALT
+ * > RETRO_MESSAGE_TYPE_PROGRESS: Indicates that message reports
+ * the progress of an internal core task. For example, in cases
+ * where a core itself handles the loading of content from a file,
+ * this may correspond to the percentage of the file that has been
+ * read. Alternatively, an audio/video playback core may use a
+ * message of type RETRO_MESSAGE_TYPE_PROGRESS to display the current
+ * playback position as a percentage of the runtime. 'Progress' type
+ * messages should therefore be displayed as a literal progress bar,
+ * where:
+ * - 'retro_message_ext.msg' is the progress bar title/label
+ * - 'retro_message_ext.progress' determines the length of
+ * the progress bar
+ * NOTE: Message type is a *hint*, and may be ignored
+ * by the frontend. If a frontend lacks support for
+ * displaying messages via alternate means than standard
+ * frontend-generated notifications, it will treat *all*
+ * messages as having the type RETRO_MESSAGE_TYPE_NOTIFICATION */
+ enum retro_message_type type;
+ /* Task progress when targeting the OSD and message is
+ * of type RETRO_MESSAGE_TYPE_PROGRESS
+ * > -1: Unmetered/indeterminate
+ * > 0-100: Current progress percentage
+ * NOTE: Since message type is a hint, a frontend may ignore
+ * progress values. Where relevant, a core should therefore
+ * include progress percentage within the message string,
+ * such that the message intent remains clear when displayed
+ * as a standard frontend-generated notification */
+ int8_t progress;
+};
+
+/* Describes how the libretro implementation maps a libretro input bind
+ * to its internal input system through a human readable string.
+ * This string can be used to better let a user configure input. */
+struct retro_input_descriptor
+{
+ /* Associates given parameters with a description. */
+ unsigned port;
+ unsigned device;
+ unsigned index;
+ unsigned id;
+
+ /* Human readable description for parameters.
+ * The pointer must remain valid until
+ * retro_unload_game() is called. */
+ const char *description;
+};
+
+struct retro_system_info
+{
+ /* All pointers are owned by libretro implementation, and pointers must
+ * remain valid until it is unloaded. */
+
+ const char *library_name; /* Descriptive name of library. Should not
+ * contain any version numbers, etc. */
+ const char *library_version; /* Descriptive version of core. */
+
+ const char *valid_extensions; /* A string listing probably content
+ * extensions the core will be able to
+ * load, separated with pipe.
+ * I.e. "bin|rom|iso".
+ * Typically used for a GUI to filter
+ * out extensions. */
+
+ /* Libretro cores that need to have direct access to their content
+ * files, including cores which use the path of the content files to
+ * determine the paths of other files, should set need_fullpath to true.
+ *
+ * Cores should strive for setting need_fullpath to false,
+ * as it allows the frontend to perform patching, etc.
+ *
+ * If need_fullpath is true and retro_load_game() is called:
+ * - retro_game_info::path is guaranteed to have a valid path
+ * - retro_game_info::data and retro_game_info::size are invalid
+ *
+ * If need_fullpath is false and retro_load_game() is called:
+ * - retro_game_info::path may be NULL
+ * - retro_game_info::data and retro_game_info::size are guaranteed
+ * to be valid
+ *
+ * See also:
+ * - RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY
+ * - RETRO_ENVIRONMENT_GET_SAVE_DIRECTORY
+ */
+ bool need_fullpath;
+
+ /* If true, the frontend is not allowed to extract any archives before
+ * loading the real content.
+ * Necessary for certain libretro implementations that load games
+ * from zipped archives. */
+ bool block_extract;
+};
+
+/* Defines overrides which modify frontend handling of
+ * specific content file types.
+ * An array of retro_system_content_info_override is
+ * passed to RETRO_ENVIRONMENT_SET_CONTENT_INFO_OVERRIDE
+ * NOTE: In the following descriptions, references to
+ * retro_load_game() may be replaced with
+ * retro_load_game_special() */
+struct retro_system_content_info_override
+{
+ /* A list of file extensions for which the override
+ * should apply, delimited by a 'pipe' character
+ * (e.g. "md|sms|gg")
+ * Permitted file extensions are limited to those
+ * included in retro_system_info::valid_extensions
+ * and/or retro_subsystem_rom_info::valid_extensions */
+ const char *extensions;
+
+ /* Overrides the need_fullpath value set in
+ * retro_system_info and/or retro_subsystem_rom_info.
+ * To reiterate:
+ *
+ * If need_fullpath is true and retro_load_game() is called:
+ * - retro_game_info::path is guaranteed to contain a valid
+ * path to an existent file
+ * - retro_game_info::data and retro_game_info::size are invalid
+ *
+ * If need_fullpath is false and retro_load_game() is called:
+ * - retro_game_info::path may be NULL
+ * - retro_game_info::data and retro_game_info::size are guaranteed
+ * to be valid
+ *
+ * In addition:
+ *
+ * If need_fullpath is true and retro_load_game() is called:
+ * - retro_game_info_ext::full_path is guaranteed to contain a valid
+ * path to an existent file
+ * - retro_game_info_ext::archive_path may be NULL
+ * - retro_game_info_ext::archive_file may be NULL
+ * - retro_game_info_ext::dir is guaranteed to contain a valid path
+ * to the directory in which the content file exists
+ * - retro_game_info_ext::name is guaranteed to contain the
+ * basename of the content file, without extension
+ * - retro_game_info_ext::ext is guaranteed to contain the
+ * extension of the content file in lower case format
+ * - retro_game_info_ext::data and retro_game_info_ext::size
+ * are invalid
+ *
+ * If need_fullpath is false and retro_load_game() is called:
+ * - If retro_game_info_ext::file_in_archive is false:
+ * - retro_game_info_ext::full_path is guaranteed to contain
+ * a valid path to an existent file
+ * - retro_game_info_ext::archive_path may be NULL
+ * - retro_game_info_ext::archive_file may be NULL
+ * - retro_game_info_ext::dir is guaranteed to contain a
+ * valid path to the directory in which the content file exists
+ * - retro_game_info_ext::name is guaranteed to contain the
+ * basename of the content file, without extension
+ * - retro_game_info_ext::ext is guaranteed to contain the
+ * extension of the content file in lower case format
+ * - If retro_game_info_ext::file_in_archive is true:
+ * - retro_game_info_ext::full_path may be NULL
+ * - retro_game_info_ext::archive_path is guaranteed to
+ * contain a valid path to an existent compressed file
+ * inside which the content file is located
+ * - retro_game_info_ext::archive_file is guaranteed to
+ * contain a valid path to an existent content file
+ * inside the compressed file referred to by
+ * retro_game_info_ext::archive_path
+ * e.g. for a compressed file '/path/to/foo.zip'
+ * containing 'bar.sfc'
+ * > retro_game_info_ext::archive_path will be '/path/to/foo.zip'
+ * > retro_game_info_ext::archive_file will be 'bar.sfc'
+ * - retro_game_info_ext::dir is guaranteed to contain a
+ * valid path to the directory in which the compressed file
+ * (containing the content file) exists
+ * - retro_game_info_ext::name is guaranteed to contain
+ * EITHER
+ * 1) the basename of the compressed file (containing
+ * the content file), without extension
+ * OR
+ * 2) the basename of the content file inside the
+ * compressed file, without extension
+ * In either case, a core should consider 'name' to
+ * be the canonical name/ID of the the content file
+ * - retro_game_info_ext::ext is guaranteed to contain the
+ * extension of the content file inside the compressed file,
+ * in lower case format
+ * - retro_game_info_ext::data and retro_game_info_ext::size are
+ * guaranteed to be valid */
+ bool need_fullpath;
+
+ /* If need_fullpath is false, specifies whether the content
+ * data buffer available in retro_load_game() is 'persistent'
+ *
+ * If persistent_data is false and retro_load_game() is called:
+ * - retro_game_info::data and retro_game_info::size
+ * are valid only until retro_load_game() returns
+ * - retro_game_info_ext::data and retro_game_info_ext::size
+ * are valid only until retro_load_game() returns
+ *
+ * If persistent_data is true and retro_load_game() is called:
+ * - retro_game_info::data and retro_game_info::size
+ * are valid until retro_deinit() returns
+ * - retro_game_info_ext::data and retro_game_info_ext::size
+ * are valid until retro_deinit() returns */
+ bool persistent_data;
+};
+
+/* Similar to retro_game_info, but provides extended
+ * information about the source content file and
+ * game memory buffer status.
+ * And array of retro_game_info_ext is returned by
+ * RETRO_ENVIRONMENT_GET_GAME_INFO_EXT
+ * NOTE: In the following descriptions, references to
+ * retro_load_game() may be replaced with
+ * retro_load_game_special() */
+struct retro_game_info_ext
+{
+ /* - If file_in_archive is false, contains a valid
+ * path to an existent content file (UTF-8 encoded)
+ * - If file_in_archive is true, may be NULL */
+ const char *full_path;
+
+ /* - If file_in_archive is false, may be NULL
+ * - If file_in_archive is true, contains a valid path
+ * to an existent compressed file inside which the
+ * content file is located (UTF-8 encoded) */
+ const char *archive_path;
+
+ /* - If file_in_archive is false, may be NULL
+ * - If file_in_archive is true, contain a valid path
+ * to an existent content file inside the compressed
+ * file referred to by archive_path (UTF-8 encoded)
+ * e.g. for a compressed file '/path/to/foo.zip'
+ * containing 'bar.sfc'
+ * > archive_path will be '/path/to/foo.zip'
+ * > archive_file will be 'bar.sfc' */
+ const char *archive_file;
+
+ /* - If file_in_archive is false, contains a valid path
+ * to the directory in which the content file exists
+ * (UTF-8 encoded)
+ * - If file_in_archive is true, contains a valid path
+ * to the directory in which the compressed file
+ * (containing the content file) exists (UTF-8 encoded) */
+ const char *dir;
+
+ /* Contains the canonical name/ID of the content file
+ * (UTF-8 encoded). Intended for use when identifying
+ * 'complementary' content named after the loaded file -
+ * i.e. companion data of a different format (a CD image
+ * required by a ROM), texture packs, internally handled
+ * save files, etc.
+ * - If file_in_archive is false, contains the basename
+ * of the content file, without extension
+ * - If file_in_archive is true, then string is
+ * implementation specific. A frontend may choose to
+ * set a name value of:
+ * EITHER
+ * 1) the basename of the compressed file (containing
+ * the content file), without extension
+ * OR
+ * 2) the basename of the content file inside the
+ * compressed file, without extension
+ * RetroArch sets the 'name' value according to (1).
+ * A frontend that supports routine loading of
+ * content from archives containing multiple unrelated
+ * content files may set the 'name' value according
+ * to (2). */
+ const char *name;
+
+ /* - If file_in_archive is false, contains the extension
+ * of the content file in lower case format
+ * - If file_in_archive is true, contains the extension
+ * of the content file inside the compressed file,
+ * in lower case format */
+ const char *ext;
+
+ /* String of implementation specific meta-data. */
+ const char *meta;
+
+ /* Memory buffer of loaded game content. Will be NULL:
+ * IF
+ * - retro_system_info::need_fullpath is true and
+ * retro_system_content_info_override::need_fullpath
+ * is unset
+ * OR
+ * - retro_system_content_info_override::need_fullpath
+ * is true */
+ const void *data;
+
+ /* Size of game content memory buffer, in bytes */
+ size_t size;
+
+ /* True if loaded content file is inside a compressed
+ * archive */
+ bool file_in_archive;
+
+ /* - If data is NULL, value is unset/ignored
+ * - If data is non-NULL:
+ * - If persistent_data is false, data and size are
+ * valid only until retro_load_game() returns
+ * - If persistent_data is true, data and size are
+ * are valid until retro_deinit() returns */
+ bool persistent_data;
+};
+
+struct retro_game_geometry
+{
+ unsigned base_width; /* Nominal video width of game. */
+ unsigned base_height; /* Nominal video height of game. */
+ unsigned max_width; /* Maximum possible width of game. */
+ unsigned max_height; /* Maximum possible height of game. */
+
+ float aspect_ratio; /* Nominal aspect ratio of game. If
+ * aspect_ratio is <= 0.0, an aspect ratio
+ * of base_width / base_height is assumed.
+ * A frontend could override this setting,
+ * if desired. */
+};
+
+struct retro_system_timing
+{
+ double fps; /* FPS of video content. */
+ double sample_rate; /* Sampling rate of audio. */
+};
+
+struct retro_system_av_info
+{
+ struct retro_game_geometry geometry;
+ struct retro_system_timing timing;
+};
+
+struct retro_variable
+{
+ /* Variable to query in RETRO_ENVIRONMENT_GET_VARIABLE.
+ * If NULL, obtains the complete environment string if more
+ * complex parsing is necessary.
+ * The environment string is formatted as key-value pairs
+ * delimited by semicolons as so:
+ * "key1=value1;key2=value2;..."
+ */
+ const char *key;
+
+ /* Value to be obtained. If key does not exist, it is set to NULL. */
+ const char *value;
+};
+
+struct retro_core_option_display
+{
+ /* Variable to configure in RETRO_ENVIRONMENT_SET_CORE_OPTIONS_DISPLAY */
+ const char *key;
+
+ /* Specifies whether variable should be displayed
+ * when presenting core options to the user */
+ bool visible;
+};
+
+/* Maximum number of values permitted for a core option
+ * > Note: We have to set a maximum value due the limitations
+ * of the C language - i.e. it is not possible to create an
+ * array of structs each containing a variable sized array,
+ * so the retro_core_option_definition values array must
+ * have a fixed size. The size limit of 128 is a balancing
+ * act - it needs to be large enough to support all 'sane'
+ * core options, but setting it too large may impact low memory
+ * platforms. In practise, if a core option has more than
+ * 128 values then the implementation is likely flawed.
+ * To quote the above API reference:
+ * "The number of possible options should be very limited
+ * i.e. it should be feasible to cycle through options
+ * without a keyboard."
+ */
+#define RETRO_NUM_CORE_OPTION_VALUES_MAX 128
+
+struct retro_core_option_value
+{
+ /* Expected option value */
+ const char *value;
+
+ /* Human-readable value label. If NULL, value itself
+ * will be displayed by the frontend */
+ const char *label;
+};
+
+struct retro_core_option_definition
+{
+ /* Variable to query in RETRO_ENVIRONMENT_GET_VARIABLE. */
+ const char *key;
+
+ /* Human-readable core option description (used as menu label) */
+ const char *desc;
+
+ /* Human-readable core option information (used as menu sublabel) */
+ const char *info;
+
+ /* Array of retro_core_option_value structs, terminated by NULL */
+ struct retro_core_option_value values[RETRO_NUM_CORE_OPTION_VALUES_MAX];
+
+ /* Default core option value. Must match one of the values
+ * in the retro_core_option_value array, otherwise will be
+ * ignored */
+ const char *default_value;
+};
+
+struct retro_core_options_intl
+{
+ /* Pointer to an array of retro_core_option_definition structs
+ * - US English implementation
+ * - Must point to a valid array */
+ struct retro_core_option_definition *us;
+
+ /* Pointer to an array of retro_core_option_definition structs
+ * - Implementation for current frontend language
+ * - May be NULL */
+ struct retro_core_option_definition *local;
+};
+
+struct retro_core_option_v2_category
+{
+ /* Variable uniquely identifying the
+ * option category. Valid key characters
+ * are [a-z, A-Z, 0-9, _, -] */
+ const char *key;
+
+ /* Human-readable category description
+ * > Used as category menu label when
+ * frontend has core option category
+ * support */
+ const char *desc;
+
+ /* Human-readable category information
+ * > Used as category menu sublabel when
+ * frontend has core option category
+ * support
+ * > Optional (may be NULL or an empty
+ * string) */
+ const char *info;
+};
+
+struct retro_core_option_v2_definition
+{
+ /* Variable to query in RETRO_ENVIRONMENT_GET_VARIABLE.
+ * Valid key characters are [a-z, A-Z, 0-9, _, -] */
+ const char *key;
+
+ /* Human-readable core option description
+ * > Used as menu label when frontend does
+ * not have core option category support
+ * e.g. "Video > Aspect Ratio" */
+ const char *desc;
+
+ /* Human-readable core option description
+ * > Used as menu label when frontend has
+ * core option category support
+ * e.g. "Aspect Ratio", where associated
+ * retro_core_option_v2_category::desc
+ * is "Video"
+ * > If empty or NULL, the string specified by
+ * desc will be used as the menu label
+ * > Will be ignored (and may be set to NULL)
+ * if category_key is empty or NULL */
+ const char *desc_categorized;
+
+ /* Human-readable core option information
+ * > Used as menu sublabel */
+ const char *info;
+
+ /* Human-readable core option information
+ * > Used as menu sublabel when frontend
+ * has core option category support
+ * (e.g. may be required when info text
+ * references an option by name/desc,
+ * and the desc/desc_categorized text
+ * for that option differ)
+ * > If empty or NULL, the string specified by
+ * info will be used as the menu sublabel
+ * > Will be ignored (and may be set to NULL)
+ * if category_key is empty or NULL */
+ const char *info_categorized;
+
+ /* Variable specifying category (e.g. "video",
+ * "audio") that will be assigned to the option
+ * if frontend has core option category support.
+ * > Categorized options will be displayed in a
+ * subsection/submenu of the frontend core
+ * option interface
+ * > Specified string must match one of the
+ * retro_core_option_v2_category::key values
+ * in the associated retro_core_option_v2_category
+ * array; If no match is not found, specified
+ * string will be considered as NULL
+ * > If specified string is empty or NULL, option will
+ * have no category and will be shown at the top
+ * level of the frontend core option interface */
+ const char *category_key;
+
+ /* Array of retro_core_option_value structs, terminated by NULL */
+ struct retro_core_option_value values[RETRO_NUM_CORE_OPTION_VALUES_MAX];
+
+ /* Default core option value. Must match one of the values
+ * in the retro_core_option_value array, otherwise will be
+ * ignored */
+ const char *default_value;
+};
+
+struct retro_core_options_v2
+{
+ /* Array of retro_core_option_v2_category structs,
+ * terminated by NULL
+ * > If NULL, all entries in definitions array
+ * will have no category and will be shown at
+ * the top level of the frontend core option
+ * interface
+ * > Will be ignored if frontend does not have
+ * core option category support */
+ struct retro_core_option_v2_category *categories;
+
+ /* Array of retro_core_option_v2_definition structs,
+ * terminated by NULL */
+ struct retro_core_option_v2_definition *definitions;
+};
+
+struct retro_core_options_v2_intl
+{
+ /* Pointer to a retro_core_options_v2 struct
+ * > US English implementation
+ * > Must point to a valid struct */
+ struct retro_core_options_v2 *us;
+
+ /* Pointer to a retro_core_options_v2 struct
+ * - Implementation for current frontend language
+ * - May be NULL */
+ struct retro_core_options_v2 *local;
+};
+
+/* Used by the frontend to monitor changes in core option
+ * visibility. May be called each time any core option
+ * value is set via the frontend.
+ * - On each invocation, the core must update the visibility
+ * of any dynamically hidden options using the
+ * RETRO_ENVIRONMENT_SET_CORE_OPTIONS_DISPLAY environment
+ * callback.
+ * - On the first invocation, returns 'true' if the visibility
+ * of any core option has changed since the last call of
+ * retro_load_game() or retro_load_game_special().
+ * - On each subsequent invocation, returns 'true' if the
+ * visibility of any core option has changed since the last
+ * time the function was called. */
+typedef bool (RETRO_CALLCONV *retro_core_options_update_display_callback_t)(void);
+struct retro_core_options_update_display_callback
+{
+ retro_core_options_update_display_callback_t callback;
+};
+
+struct retro_game_info
+{
+ const char *path; /* Path to game, UTF-8 encoded.
+ * Sometimes used as a reference for building other paths.
+ * May be NULL if game was loaded from stdin or similar,
+ * but in this case some cores will be unable to load `data`.
+ * So, it is preferable to fabricate something here instead
+ * of passing NULL, which will help more cores to succeed.
+ * retro_system_info::need_fullpath requires
+ * that this path is valid. */
+ const void *data; /* Memory buffer of loaded game. Will be NULL
+ * if need_fullpath was set. */
+ size_t size; /* Size of memory buffer. */
+ const char *meta; /* String of implementation specific meta-data. */
+};
+
+#define RETRO_MEMORY_ACCESS_WRITE (1 << 0)
+ /* The core will write to the buffer provided by retro_framebuffer::data. */
+#define RETRO_MEMORY_ACCESS_READ (1 << 1)
+ /* The core will read from retro_framebuffer::data. */
+#define RETRO_MEMORY_TYPE_CACHED (1 << 0)
+ /* The memory in data is cached.
+ * If not cached, random writes and/or reading from the buffer is expected to be very slow. */
+struct retro_framebuffer
+{
+ void *data; /* The framebuffer which the core can render into.
+ Set by frontend in GET_CURRENT_SOFTWARE_FRAMEBUFFER.
+ The initial contents of data are unspecified. */
+ unsigned width; /* The framebuffer width used by the core. Set by core. */
+ unsigned height; /* The framebuffer height used by the core. Set by core. */
+ size_t pitch; /* The number of bytes between the beginning of a scanline,
+ and beginning of the next scanline.
+ Set by frontend in GET_CURRENT_SOFTWARE_FRAMEBUFFER. */
+ enum retro_pixel_format format; /* The pixel format the core must use to render into data.
+ This format could differ from the format used in
+ SET_PIXEL_FORMAT.
+ Set by frontend in GET_CURRENT_SOFTWARE_FRAMEBUFFER. */
+
+ unsigned access_flags; /* How the core will access the memory in the framebuffer.
+ RETRO_MEMORY_ACCESS_* flags.
+ Set by core. */
+ unsigned memory_flags; /* Flags telling core how the memory has been mapped.
+ RETRO_MEMORY_TYPE_* flags.
+ Set by frontend in GET_CURRENT_SOFTWARE_FRAMEBUFFER. */
+};
+
+/* Used by a libretro core to override the current
+ * fastforwarding mode of the frontend */
+struct retro_fastforwarding_override
+{
+ /* Specifies the runtime speed multiplier that
+ * will be applied when 'fastforward' is true.
+ * For example, a value of 5.0 when running 60 FPS
+ * content will cap the fast-forward rate at 300 FPS.
+ * Note that the target multiplier may not be achieved
+ * if the host hardware has insufficient processing
+ * power.
+ * Setting a value of 0.0 (or greater than 0.0 but
+ * less than 1.0) will result in an uncapped
+ * fast-forward rate (limited only by hardware
+ * capacity).
+ * If the value is negative, it will be ignored
+ * (i.e. the frontend will use a runtime speed
+ * multiplier of its own choosing) */
+ float ratio;
+
+ /* If true, fastforwarding mode will be enabled.
+ * If false, fastforwarding mode will be disabled. */
+ bool fastforward;
+
+ /* If true, and if supported by the frontend, an
+ * on-screen notification will be displayed while
+ * 'fastforward' is true.
+ * If false, and if supported by the frontend, any
+ * on-screen fast-forward notifications will be
+ * suppressed */
+ bool notification;
+
+ /* If true, the core will have sole control over
+ * when fastforwarding mode is enabled/disabled;
+ * the frontend will not be able to change the
+ * state set by 'fastforward' until either
+ * 'inhibit_toggle' is set to false, or the core
+ * is unloaded */
+ bool inhibit_toggle;
+};
+
+/* Callbacks */
+
+/* Environment callback. Gives implementations a way of performing
+ * uncommon tasks. Extensible. */
+typedef bool (RETRO_CALLCONV *retro_environment_t)(unsigned cmd, void *data);
+
+/* Render a frame. Pixel format is 15-bit 0RGB1555 native endian
+ * unless changed (see RETRO_ENVIRONMENT_SET_PIXEL_FORMAT).
+ *
+ * Width and height specify dimensions of buffer.
+ * Pitch specifices length in bytes between two lines in buffer.
+ *
+ * For performance reasons, it is highly recommended to have a frame
+ * that is packed in memory, i.e. pitch == width * byte_per_pixel.
+ * Certain graphic APIs, such as OpenGL ES, do not like textures
+ * that are not packed in memory.
+ */
+typedef void (RETRO_CALLCONV *retro_video_refresh_t)(const void *data, unsigned width,
+ unsigned height, size_t pitch);
+
+/* Renders a single audio frame. Should only be used if implementation
+ * generates a single sample at a time.
+ * Format is signed 16-bit native endian.
+ */
+typedef void (RETRO_CALLCONV *retro_audio_sample_t)(int16_t left, int16_t right);
+
+/* Renders multiple audio frames in one go.
+ *
+ * One frame is defined as a sample of left and right channels, interleaved.
+ * I.e. int16_t buf[4] = { l, r, l, r }; would be 2 frames.
+ * Only one of the audio callbacks must ever be used.
+ */
+typedef size_t (RETRO_CALLCONV *retro_audio_sample_batch_t)(const int16_t *data,
+ size_t frames);
+
+/* Polls input. */
+typedef void (RETRO_CALLCONV *retro_input_poll_t)(void);
+
+/* Queries for input for player 'port'. device will be masked with
+ * RETRO_DEVICE_MASK.
+ *
+ * Specialization of devices such as RETRO_DEVICE_JOYPAD_MULTITAP that
+ * have been set with retro_set_controller_port_device()
+ * will still use the higher level RETRO_DEVICE_JOYPAD to request input.
+ */
+typedef int16_t (RETRO_CALLCONV *retro_input_state_t)(unsigned port, unsigned device,
+ unsigned index, unsigned id);
+
+/* Sets callbacks. retro_set_environment() is guaranteed to be called
+ * before retro_init().
+ *
+ * The rest of the set_* functions are guaranteed to have been called
+ * before the first call to retro_run() is made. */
+RETRO_API void retro_set_environment(retro_environment_t);
+RETRO_API void retro_set_video_refresh(retro_video_refresh_t);
+RETRO_API void retro_set_audio_sample(retro_audio_sample_t);
+RETRO_API void retro_set_audio_sample_batch(retro_audio_sample_batch_t);
+RETRO_API void retro_set_input_poll(retro_input_poll_t);
+RETRO_API void retro_set_input_state(retro_input_state_t);
+
+/* Library global initialization/deinitialization. */
+RETRO_API void retro_init(void);
+RETRO_API void retro_deinit(void);
+
+/* Must return RETRO_API_VERSION. Used to validate ABI compatibility
+ * when the API is revised. */
+RETRO_API unsigned retro_api_version(void);
+
+/* Gets statically known system info. Pointers provided in *info
+ * must be statically allocated.
+ * Can be called at any time, even before retro_init(). */
+RETRO_API void retro_get_system_info(struct retro_system_info *info);
+
+/* Gets information about system audio/video timings and geometry.
+ * Can be called only after retro_load_game() has successfully completed.
+ * NOTE: The implementation of this function might not initialize every
+ * variable if needed.
+ * E.g. geom.aspect_ratio might not be initialized if core doesn't
+ * desire a particular aspect ratio. */
+RETRO_API void retro_get_system_av_info(struct retro_system_av_info *info);
+
+/* Sets device to be used for player 'port'.
+ * By default, RETRO_DEVICE_JOYPAD is assumed to be plugged into all
+ * available ports.
+ * Setting a particular device type is not a guarantee that libretro cores
+ * will only poll input based on that particular device type. It is only a
+ * hint to the libretro core when a core cannot automatically detect the
+ * appropriate input device type on its own. It is also relevant when a
+ * core can change its behavior depending on device type.
+ *
+ * As part of the core's implementation of retro_set_controller_port_device,
+ * the core should call RETRO_ENVIRONMENT_SET_INPUT_DESCRIPTORS to notify the
+ * frontend if the descriptions for any controls have changed as a
+ * result of changing the device type.
+ */
+RETRO_API void retro_set_controller_port_device(unsigned port, unsigned device);
+
+/* Resets the current game. */
+RETRO_API void retro_reset(void);
+
+/* Runs the game for one video frame.
+ * During retro_run(), input_poll callback must be called at least once.
+ *
+ * If a frame is not rendered for reasons where a game "dropped" a frame,
+ * this still counts as a frame, and retro_run() should explicitly dupe
+ * a frame if GET_CAN_DUPE returns true.
+ * In this case, the video callback can take a NULL argument for data.
+ */
+RETRO_API void retro_run(void);
+
+/* Returns the amount of data the implementation requires to serialize
+ * internal state (save states).
+ * Between calls to retro_load_game() and retro_unload_game(), the
+ * returned size is never allowed to be larger than a previous returned
+ * value, to ensure that the frontend can allocate a save state buffer once.
+ */
+RETRO_API size_t retro_serialize_size(void);
+
+/* Serializes internal state. If failed, or size is lower than
+ * retro_serialize_size(), it should return false, true otherwise. */
+RETRO_API bool retro_serialize(void *data, size_t size);
+RETRO_API bool retro_unserialize(const void *data, size_t size);
+
+RETRO_API void retro_cheat_reset(void);
+RETRO_API void retro_cheat_set(unsigned index, bool enabled, const char *code);
+
+/* Loads a game.
+ * Return true to indicate successful loading and false to indicate load failure.
+ */
+RETRO_API bool retro_load_game(const struct retro_game_info *game);
+
+/* Loads a "special" kind of game. Should not be used,
+ * except in extreme cases. */
+RETRO_API bool retro_load_game_special(
+ unsigned game_type,
+ const struct retro_game_info *info, size_t num_info
+);
+
+/* Unloads the currently loaded game. Called before retro_deinit(void). */
+RETRO_API void retro_unload_game(void);
+
+/* Gets region of game. */
+RETRO_API unsigned retro_get_region(void);
+
+/* Gets region of memory. */
+RETRO_API void *retro_get_memory_data(unsigned id);
+RETRO_API size_t retro_get_memory_size(unsigned id);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif